DE102019110013A1 - PERMANENT MAGNETIC ROTARY MACHINE AND ELECTRICAL ROTATION MACHINE - Google Patents

Abstract

An object of the present invention is to provide a permanent magnet rotor capable of reducing harmonic components of the waveform of the magnetic flux density distribution present in the air gap of a rotary electric machine, as well as a rotary electric machine having such a permanent magnet rotor.

Description

FIELD OF THE INVENTION

The present invention relates to a permanent magnet rotor and a rotary electric machine (electric motor). In particular, the present invention relates to a permanent magnet rotor in which permanent magnets are embedded in a rotor core, and an electric motor having such a permanent magnet rotor.

BACKGROUND OF THE INVENTION

Electric motors using a permanent magnet rotor, such as the Interior Permanent Magnet (IPM) motor, preferably have a low torque ripple, which causes vibration and noise during operation, and low iron loss, which reduces engine efficiency. For this purpose, it is effective to form the waveform of a magnetic flux density distribution formed in the air gap between the permanent magnet rotor and the stator closer to a sine wave, thereby reducing harmonic components of the waveform.

For example, Patent Document 1, which relates to a permanent magnet rotor in which permanent magnets are embedded in multiple layers for each magnetic pole in a rotor core, describes relationships between dimensions and the remanence (residual magnetic flux density) of the permanent magnets of the respective layer and other parameters that govern the magnetic flux density distribution in the Forming air gap closer to a sine wave, whereby the ripple of the torque and the cogging torque (English cogging torque) can be reduced. In an exemplary embodiment, dummy slot regions in which no permanent magnet is embedded are respectively formed in a part of each of the slots in which permanent magnets are disposed except those permanent magnets which form the outermost layer on the peripheral side of the rotor core such that the blank slot areas increase in size with their location from the outer peripheral side to the inner peripheral side of the rotor core, and that a total magnetic flux density generated by the permanent magnet layers in the case where the permanent magnet layers are built in an electric motor so is set to be larger, the further the position of the permanent magnet layer from the outer peripheral side to the inner peripheral side of the rotor core progresses. In another exemplary embodiment, the remanence of the permanent magnets is set to decrease with the position of the permanent magnet layer as it progresses from the outer peripheral side to the inner peripheral side of the rotor core, and so that the total magnetic flux density provided by the permanent magnet layers in the case where the permanent magnet layers are built in an electric motor, the larger the position of the permanent magnet layer proceeds from the outer peripheral side to the inner peripheral side of the rotor core, the larger it is set.

Patent Document 1: JP-A-2002-78259

BRIEF SUMMARY OF THE INVENTION

As described above, in Patent Document 1, the waveform of a magnetic flux density distribution in the air gap is approximately formed on a sine wave by setting the entire magnetic flux generated by the permanent magnet layers in the case where the permanent magnet layers are built in an electric motor The higher the position of the permanent magnet layer from the outer peripheral side to the inner peripheral side of the rotor core, the higher the total magnetic flux is, by adjusting the lengths and the remanences of the permanent magnets disposed in layers in the rotor core. However, the present inventors have found in investigations that a further reduction of the harmonic components is possible which can not be achieved by the adjustment of the relationship between the total magnetic fluxes of the respective permanent magnetic layers as described above.

An object to be achieved by the present invention is to provide a permanent magnet rotor capable of reducing harmonic components of the waveform of a magnetic flux density distribution formed in the air gap of an electric motor, and an electric motor having such a permanent magnet rotor.

• einem Rotorkern; und
• mehreren Permanentmagneten, die in den Rotorkern eingebettet sind und jeweils einen Magnetpol bilden,
• wobei die mehreren Permanentmagneten jeweils eine Bogenform aufweisen, die zu einer inneren Umfangsseite der Rotorkerns hin konvex ist, und in drei oder mehr Lagen von einer äußeren Umfangsseite zur inneren Umfangsseite des Rotorkerns angeordnet sind, und
• Öffnungswinkel θ_M1 , θ_M2 und θ_M3 der Bogenformen der in der ersten, zweiten bzw. dritten Lage von der äußeren Umfangsseite zur inneren Umfangsseite des Rotorkerns angeordneten Permanentmagnete die folgende Beziehung erfüllen: $${\mathrm{\theta }}_{\text{M}3}<{\mathrm{\theta }}_{\text{M}2}<{\mathrm{\theta }}_{\text{M}1}{\text{ wenn R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}},$$
  
  oder

$${\mathrm{<figure-callout\; id="3"\; label="\theta \; M"\; filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\theta </figure-callout>}}_{\text{M}}\le {\mathrm{<figure-callout\; id="1"\; label="\theta \; M"\; filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png"\; state="\{\{state\}\}">\theta </figure-callout>}}_{\text{M}}<{\mathrm{<figure-callout\; id="2"\; label="\theta \; M"\; filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\theta </figure-callout>}}_{\text{M}}{\text{ wenn R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}$$

wobei R_θ ein Abstand vom Rotationszentrum des Rotorkerns bis zu einer mittleren Position der Brennpunkte (Krümmungsmittelpunkte) der Bogenformen der in der ersten, zweiten bzw. dritten Lage angeordneten Permanentmagnete ist, R ein Abstand vom Rotationszentrum des Rotorkerns zum äußeren Umfang der Rotorkerns ist, n die Anzahl der Magnetpole ist, und θ_r = 180°/n ist.To achieve the above object, the present invention proposes a first permanent magnet rotor, comprising:

• a rotor core; and
• a plurality of permanent magnets embedded in the rotor core and each forming a magnetic pole,
• wherein the plurality of permanent magnets each have an arcuate shape that is convex toward an inner peripheral side of the rotor cores, and are arranged in three or more layers from an outer peripheral side to the inner peripheral side of the rotor core, and
• opening angle θ _M1 . θ _M2 and θ _M3 the arc shapes of the permanent magnets disposed in the first, second and third positions from the outer peripheral side to the inner peripheral side of the rotor core, respectively, satisfy the following relationship: $${\mathrm{\theta }}_{\text{<figure-callout id="3" label="M" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">M</figure-callout>}3}<{\mathrm{<figure-callout\; id="2"\; label="\theta \; M"\; filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\theta \; </figure-callout>}}_{\text{M}}<{\mathrm{<figure-callout\; id="1"\; label="\theta \; M"\; filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png"\; state="\{\{state\}\}">\theta \; </figure-callout>}}_{\text{M}}{\text{if R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}.$$
  
  or

$${\mathrm{<figure-callout\; id="3"\; label="\theta \; M"\; filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\theta \; </figure-callout>}}_{\text{M}}\le {\mathrm{<figure-callout\; id="1"\; label="\theta \; M"\; filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png"\; state="\{\{state\}\}">\theta \; </figure-callout>}}_{\text{M}}<{\mathrm{<figure-callout\; id="2"\; label="\theta \; M"\; filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\theta \; </figure-callout>}}_{\text{M}}{\text{if R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}$$

in which R _θ is a distance from the center of rotation of the rotor core to a middle position of the foci (centers of curvature) of the arc shapes of the permanent magnets disposed in the first, second and third layers, respectively; R is a distance from the center of rotation of the rotor core to the outer circumference of the rotor core, n is the number of magnetic poles, and θ _r = 180 ° / n.

oder $$\text{Br}3\le \text{Br}1<\text{Br}2{\text{ wenn R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}.$$

Here, the remanences meet Br1 . Br2 and Br3 Preferably, the permanent magnets disposed in the first, second, and third layers from the outer circumferential side of the rotor core have the following relationship: $$\text{<figure-callout id="3" label="br" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}3<\text{<figure-callout id="2" label="br" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}2<\text{<figure-callout id="1" label="br" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">br</figure-callout>}1{\text{if R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}.$$

or $$\text{<figure-callout id="3" label="br" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}3\le \text{<figure-callout id="1" label="br" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">br</figure-callout>}1<\text{<figure-callout id="2" label="br" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}2{\text{if R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}},$$

• einem Rotorkern; und
• Mehreren Permanentmagneten, die in dem Rotorkern eingebettet sind und jeweils einen Magnetpol darstellen,
• wobei die mehreren Permanentmagnete jeweils eine Bogenform aufweisen derart, dass sie zu einer inneren Umfangsseite des Rotorkerns hin konvex sind, und in drei oder
• mehr Lagen von einer äußeren Umfangsseite zur inneren Umfangsseite des Rotorkerns angeordnet sind, und
• Remanenzen Br1, Br2 und Br3 der in der ersten, zweiten bzw. dritten Lage von der äußeren Umfangsseite des Rotorkerns angeordneten Permanentmagnete die folgende Beziehung erfüllen: $$\text{Br}3<\text{Br}2<\text{Br}1{\text{ wenn R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}},$$
  
  oder

$$\text{<figure-callout id="3" label="Br" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">Br</figure-callout>}3\le \text{Br}1<\text{Br}2{\text{ wenn R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}$$

wobei R_θ ein Abstand vom Rotationszentrum des Rotorkerns zu einer mittleren Position der Brennpunkte der Bogenformen der in der ersten, zweiten bzw. dritten Lage angeordneten Permanentmagnete ist, R ein Abstand vom Rotationszentrum des Rotorkerns zum äußeren Umfang des Rotorkerns ist, n die Anzahl der Magnetpole ist, und θ_r = 180°/n ist.In addition, a second permanent magnet rotor according to the present invention is a permanent magnet rotor comprising:

• a rotor core; and
• A plurality of permanent magnets embedded in the rotor core and each representing a magnetic pole,
• wherein the plurality of permanent magnets each have an arc shape such that they are convex toward an inner peripheral side of the rotor core, and in three or three
• more layers are arranged from an outer peripheral side to the inner peripheral side of the rotor core, and
• remanence Br1 . Br2 and Br3 the permanent magnets disposed in the first, second and third positions, respectively, from the outer peripheral side of the rotor core satisfy the following relationship: $$\text{<figure-callout id="3" label="br" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}3<\text{<figure-callout id="2" label="br" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}2<\text{<figure-callout id="1" label="br" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">br</figure-callout>}1{\text{if R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}.$$
  
  or

$$\text{<figure-callout id="3" label="br" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}3\le \text{<figure-callout id="1" label="br" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">br</figure-callout>}1<\text{<figure-callout id="2" label="br" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}2{\text{if R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}$$

in which R _θ is a distance from the center of rotation of the rotor core to a middle position of the focal points of the arcuate shapes of the permanent magnets disposed in the first, second and third layers, respectively; R a distance from the center of rotation of the rotor core to the outer circumference of the rotor core, n is the number of magnetic poles, and θ _r = 180 ° / n.

• einem Rotorkern; und
• mehreren Permanentmagneten, welche in dem Rotorkern eingebettet sind und jeweils einen Magnetpol darstellen,
• wobei die mehreren Permanentmagnete jeweils eine derartige Bogenform aufweisen, dass sie zu einer inneren Umfangsseite des Rotorkerns hin konvex sind, und in zwei Lagen von der äußeren Umfangsseite zur inneren Umfangsseite angeordnet sind, und Öffnungswinkel θ_M1 und θ_M2 der Bogenformen der in der ersten bzw. zweiten Lage von der äußeren Umfangsseite des Rotorkerns angeordneten Permanentmagnete die folgende Beziehung erfüllen: $${\mathrm{\theta }}_{\text{M}2}<{\mathrm{\theta }}_{\text{<figure-callout id="1" label="M" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">M</figure-callout>}1}.$$
  

Further, a third permanent magnet rotor according to the present invention is a permanent magnet rotor comprising:

• a rotor core; and
• a plurality of permanent magnets which are embedded in the rotor core and each represent a magnetic pole,
• wherein the plurality of permanent magnets each have such an arcuate shape as to be convex toward an inner peripheral side of the rotor core, and are arranged in two layers from the outer peripheral side to the inner peripheral side, and opening angles θ _M1 and θ _M2 the arc shapes of the permanent magnets disposed in the first and second positions from the outer circumferential side of the rotor core satisfy the following relationship: $${\mathrm{\theta }}_{\text{M}2}<{\mathrm{\theta }}_{\text{M}1},$$
  

Here, the remanences meet Br1 and Br2 Preferably, the permanent magnets disposed in the first and second layers from the outer peripheral side of the rotor core have the following relationship: $$\text{<figure-callout id="2" label="br" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}2<\text{<figure-callout id="1" label="br" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">br</figure-callout>}1.$$

In addition, it is preferable that the foci (centers of curvature) of the arc shapes of the plurality of permanent magnets are arranged separately from the outer peripheral side to the inner peripheral side of the rotor core in the same order as the plurality of permanent magnets from the outer peripheral side to the inner peripheral side of the rotor core.

Further, it is preferable that the plurality of permanent magnets include metal magnets.

• dem oben beschriebenen Permanentmagnetrotor; und
• einem Stator, welcher derart angeordnet ist, dass ein Luftspalt zwischen dem Permanentmagnetrotor und dem Stator gebildet wird.

An electric rotary machine (electric motor) according to the present invention is an electric motor having:

• the above-described permanent magnet rotor; and
• a stator which is arranged such that an air gap between the permanent magnet rotor and the stator is formed.

Here, it is preferable that the electric motor has an overall harmonic distortion of less than or equal to 23% in a waveform of the magnetic flux density distribution formed by the plurality of permanent magnets in the air gap.

In the first, second and third permanent magnet rotors according to the present invention described above, the plurality of arc-shaped permanent magnets are disposed in layers in the rotor core, and the opening angles of the permanent magnets of the respective layers and / or their remanences satisfy the prescribed relationship. Thus, when the permanent magnet rotor is installed in an electric motor, the harmonic components in the magnetic flux density distribution formed by the permanent magnets in the air gap between the permanent magnets and the stator are reduced, and a waveform near a sine wave can be obtained. As a result, torque ripple and iron loss in the electric motor can be reduced.

In the case that the foci (centers of curvature) of the arc shapes of the plurality of permanent magnets are arranged separately from the outer peripheral side to the inner peripheral side of the rotor core in the same order as the plurality of permanent magnets, the closer the position of one becomes, the closer the inter-gap between the permanent magnets becomes Rotor-d axis along the longitudinal direction of the arc shapes of the permanent magnets comes. As a result, a reluctance torque generated in the permanent magnet rotor is increased. This feature also has an effect on reducing torque ripple.

In the case that the plural permanent magnets include metal magnets, the remanence of the permanent magnet may be high. Thus, a large magnetic torque can be ensured even if the permanent magnets are thinned. As a result, the thicknesses of the permanent magnets can be made smaller than the values beyond which the reluctance torque is reduced, and thereby the reduction of the reluctance torque can be suppressed.

The electric motor according to the present invention includes any one of the above-described first, second or third permanent magnet rotors according to the present invention. Thus, harmonic components in the magnetic flux density distribution generated by the permanent magnets in the air gap between the permanent magnet rotor and the stator, and a waveform near a sine wave can be obtained. As a result, the torque ripple and the iron loss of the electric motor are reduced, and hence the amount of vibration and noise are low and the efficiency is high.

In the case that the total harmonic distortion in a waveform of the magnetic flux density distribution generated by the plurality of permanent magnets in the air gap is less than or equal to 23%, the harmonic components in the magnetic flux density distribution are sufficiently reduced because the aperture angles and / or the remanences the permanent magnets of the respective layers in the permanent magnet rotor satisfy the above relationship, and therefore the electric motor can be effectively reduced in vibration and noise.

list of figures

• 1 FIG. 10 is a horizontal cross-sectional view showing the configurations of a permanent magnet rotor and an electric motor according to an embodiment of the present invention. FIG.
• 2 is an enlarged view of a part of 1 as a cross-sectional view.
• 3 is a diagram for describing parameters that define an arrangement and shapes of permanent magnets.
• 4 Fig. 12 is a diagram for describing waveform parameters for use in examining a waveform of the magnetic flux density distribution, and shows an initial waveform that is based on the examples.
• 5 is a graph showing the distribution of the total harmonic distortion when the waveform parameters α and β be varied.
• 6 is a graph showing the distribution of the total harmonic distortion when the waveform parameters α and γ be varied.
• 7 is a graph showing the distribution of the total harmonic distortion when the waveform parameters A and B be varied.
• 8A and 8B show an arrangement of the permanent magnets or a waveform of the magnetic flux density distribution in model 1 ,
• 9A and 9B show an arrangement of the permanent magnets or a waveform of the magnetic flux density distribution in model 2 ,
• 10A and 10B show an arrangement of the permanent magnets or a waveform of the magnetic flux density distribution in model 3 ,
• 11 is a graph comparing iron losses without consumers of the models 1 to 3 ,
• 12A to 12E Fig. 12 shows arrangements of the permanent magnets which provide magnetic flux density distribution waveforms in which the contributions of the harmonic components are small for various positions of the center of the arc shapes of the permanent magnets; the position of the center of the arc shapes of the permanent magnets migrates in the order of 12A . 12B . 12C . 12D and 12E away from the rotor core.
• (a) to (f) in 13 show rotor core models with various types of magnet arrangement, namely (a) single layer, V-shaped arrangement 1 , ( b ) Single layer, V-shaped arrangement- 2 , (c) single layer, V-shaped arrangement- 3 , ( d ) Double layer, V-shaped arrangement, ( e ) V-arrangement and ( f ) Triple layer, circular arc arrangement.
• (a) to (f) in 14 show waveforms of the magnetic flux density distribution of the respective models.
• (a) to (f) in 15 are graphs representing the contributions of a fundamental wave and harmonic components of the ( a ) to ( f ) in 14 show waveforms shown.
• 16 is a graph for comparison between the values of the total harmonic distortion of in ( a ) to ( f ) in 14 shown waveforms.
• (a) to (f) in 17 are graphs that each show the contributions of a fundamental wave and harmonic components to iron loss without consumers in each model.
• 18 is a graph to compare iron losses without consumers of the respective models.

DETAILED DESCRIPTION OF THE INVENTION

A permanent magnet rotor 10 and an electric motor 1 according to one embodiment of the present invention will be described below in more detail with reference to the drawings.

[Configuration of the electric motor]

1 schematically illustrates the electric motor 1 according to the embodiment of the present invention. The electric motor 1 includes the permanent magnet rotor 10 according to the embodiment of the present invention. Although this description refers to the case that the rotary electric machine 1 is a motor, the same configuration is also applicable when it is a generator.

The electric motor 1 is configured as a motor with internal permanent magnet (IPM). The motor 1 includes a stator (stand) 30 , which is shaped like a hollow cylinder, and the rotor (permanent magnet rotor, rotor) 10 which is in the cavity of the stator 30 concentric with the stator 30 arranged, and is rotatably supported about the axis.

The stator 30 includes a stator core 31 and coils (not shown). The stator core 31 is formed by stacking several layers of electromagnetic steel plates and integrally includes a circular yoke portion (back yoke portion) 31a and several teeth 31b coming from the yoke area 31a protrude. Around the outer perimeters of the teeth 31b each coils are wound.

The rotor 10 includes a rotor core 11 with an approximately cylindrical outer shape and a plurality of permanent magnets 16 . 17 and 18 in the rotor core 11 are embedded. A hollow area 12 through which a wave 40 can be used, passes through the rotor core 11 center. An air gap 50 is between the teeth 31b of the stator core 31 and the outer peripheral surface 11a of the rotor core 11 kept such that the rotor 10 in the cavity of the stator 30 is recorded concentrically. Next is the configuration of the rotor 10 described in more detail.

[Outline of the configuration of the permanent magnet rotor]

As described above, the rotor (permanent magnet rotor) includes 10 the rotor core 11 and the permanent magnets 16 . 17 and 18 , 1 and 2 show the configuration of the rotor 10 , and 2 shows a magnetic pole of the rotor 10 , In the 1 shown general configuration of the rotor 10 is such that a plurality of (in this example eight) magnetic poles are successively arranged in a rotationally symmetric manner such that the polarities of the sets of the permanent magnets 16 . 17 and 18 alternate the respective magnetic poles. In the following description, expressions, the directions of a rotating body such as "circumferential direction", "inner circumference", "outer circumference" and "radial direction" mean directions with respect to the rotor core 11 unless otherwise stated.

The rotor core 11 is formed by stacking a plurality of electromagnetic steel sheets and has an approximately cylindrical outer peripheral surface 11a on. slots 13 . 14 and 15 and river barriers 20 are in the rotor core 11 formed as spaces that pass through it in the axial direction or are hollowed out in it. The permanent magnets 16 . 17 and 18 are in the corresponding slots 13 . 14 and 15 embedded.

The slots 13 . 14 and 15 each have an arc shape to the inner peripheral side (side of the rotation center) of the rotor core 11 is convex. The permanent magnets 16 . 17 and 18 in the respective slots 13 . 14 respectively. 15 are arranged, also each have an arc shape, the inner peripheral side of the rotor core 11 is convex, so that they become the shape of the slits 13 . 14 respectively. 15 are compliant. There is no particular limitation on the shape of the slots 13 . 14 and 15 and the permanent magnets 16 . 17 and 18 as long as each of them has an arc shape facing the inner peripheral side of the rotor core 11 is convex, namely has a slightly curved shape, so that it has only a convex portion in a horizontal cross section of the rotor 10 from the outer peripheral side of the rotor core 11 towards the inner peripheral side is convex. In the embodiment, each of the slots has 13 . 14 and 15 and the permanent magnets 16 . 17 and 18 an approximate circular arc shape.

There is no particular limitation on the number of layers for each set of slots 13 . 14 and 15 and every set of permanent magnets 16 . 17 and 18 as long as each set of slots 13 . 14 and 15 and every set of permanent magnets 16 . 17 and 18 is present in two or more layers; in the embodiment, each set of slots is located 13 . 14 and 15 and every set of permanent magnets 16 . 17 and 18 in three layers. In particular, the slots 13 . 14 and 15 in this order from the outer peripheral side of the rotor core 11 arranged in a first layer, a second layer or a third layer, and the permanent magnets 16 . 17 and 18 are in the respective slots 13 . 14 and 15 embedded. The permanent magnets 16 . 17 and 18 , which constitute a magnetic pole, have the same polarity.

Each of the slots 13 . 14 and 15 the first layer, the second layer, and the third layer is in the circumferential direction of the rotor core 11 divided into two areas. Two sections of each of the permanent magnets 16 . 17 and 18 are in the respective subregions of the associated one of the slots 13 . 14 and 15 embedded. In each of the first layer and the second layer are the subregions of the slot 13 respectively. 14 in the circumferential direction of the rotor core 11 adjacent to each other 11 with a bridge in between 21 , In the third location are river barriers 20 between the two sections of the slot 15 arranged. In the embodiment, each of the constituent elements of the rotor is like each of the slots 13 . 14 and 15 the respective position, each of the permanent magnets 16 . 17 and 18 , or the pair of flow barriers, with respect to a "d" axis extending in the radial direction of the rotor core (in FIG 2 by the symbol " d 'Marked) formed symmetrically.

The slots 13 . 14 or 15 and the permanent magnets 16 . 17 or 18 Each layer need not always be divided into two areas and may instead be a continuous slot or permanent magnet. In the latter case, those below can be used for the subregions of the permanent magnets 16 . 17 and 18 defined parameters such as opening angle θ _M1 to θ _M3 and focal points (centers of curvature) c1 to c3 as well for the entire, continuous permanent magnets 16 . 17 and 18 To be defined.

There is no particular limitation on the composition of the permanent magnets 16 . 17 and 18 ; in the embodiment, the permanent magnets include 16 . 17 and 18 Metal magnets. That is, there are no metal oxides or organic compounds intentionally in the permanent magnets 16 . 17 and 18 except in the vicinity of the surfaces, and are continuous bodies of a metal magnetic material.

An emergence (eg emergence 15a) is from an outer edge of each portion of each slot 13 . 14 or 15 inwardly and in contact with the end surface of the portion of the associated permanent magnet 16 . 17 respectively. 18 for positioning and holding the partial area of the permanent magnet 16 . 17 respectively. 18 in the partial area of the slot 13 . 14 respectively. 15 , In the second and third layers is at each portion of the slot 14 respectively. 15 a room 22 that does not depend on any part of the associated permanent magnet 17 respectively. 18 is occupied, as an end portion kept free, on the side of the d-axis of the rotor. The rooms 22 play a role in increasing the reluctance torque by effectively taking advantage of the permanent magnets 17 and 18 generated magnetic fluxes.

In the river barriers 20 between the sections of the slot 15 are formed of the third layer, no permanent magnets are embedded, whereby the flow barriers 20 be kept hollow. Alternatively, the river locks 20 filled with a non-magnetic material. The river locks 20 play a role in increasing the in the rotor 10 generated reluctance torque, in which it detects the magnetic resistance of a magnetic path of the d-axis of the rotor 10 increase. The river locks 20 are not essential and are not limited to any particular form, even if they are trained.

bridges 21 are integral with the rotor core 11 formed at such positions that every bridge 21 one on the inner peripheral side of the slot 13 . 14 respectively. 15 or the river barrier 20 and an area located on its or its outer peripheral side connects. Every bridge 21 plays a role in preventing that on the outer circumferential side of the slot 13 . 14 respectively. 15 or the river barrier 20 located part of the rotor core 11 by centrifugal forces from the areas of the rotor core 11 on its or its inner peripheral side peels off and in preventing that in the slot 13 . 14 respectively. 15 embedded permanent magnet 16 . 17 respectively. 18 flies away by the centrifugal force when the rotor 10 is rotated about its axis.

The outer peripheral surface 11a of the rotor core 11 is with dents 11b which, like grooves, spring back toward the inner peripheral side, near its axes (hereinafter referred to as q 'axes) (see 2 )), which are spaced from the d-axis of the rotor by 90 ° in terms of an electrical angle, namely in the vicinity of the outer peripheral side ends of the slot 15 the third location. The dents 11b are not essential, and by the formed dents 11b caused influence is described below.

[Configuration of permanent magnets]

In the rotor 10 According to the embodiment, the arc-shaped permanent magnets 16 . 17 and 18 arranged in multiple layers and the shapes, the layout and the remanences (residual magnetic flux densities) of the permanent magnets 16 . 17 and 18 the respective layers are set so that prescribed relationships are satisfied, whereby harmonic components in the waveform of one through the permanent magnets 16 . 17 and 18 in the air gap 50 between the stator 30 and the rotor 10 of the motor 1 generated magnetic flux density distribution can be reduced. As described below in the examples, the harmonic components can be obtained by arranging the arc-shaped permanent magnets 16 . 17 and 18 of the multiple layers are reduced more effectively in a prescribed manner than in the cases where the V-shaped arrangement, the V-shaped arrangement, etc. are used, which have been proposed as arrangements of permanent magnets favorable to the reduction of harmonic components.

The configuration of the permanent magnets will be explained mainly with reference to FIG 2 and 3 more specifically, with the main focus on the above-described case of providing the permanent magnets 16 . 17 and 18 in three layers. Although in the rotor 10 according to the embodiment, the number of poles is equal to eight, as mentioned above, there is no particular limitation on the number of poles as long as it is an even number greater than or equal to four; it can be four or six, for example. In the following description, however, the relationships become as to the opening angles of the arc shapes and the magnetic flux densities of the permanent magnets 16 . 17 and 18 the respective positions as a function of the number n poles described.

Opening angle of the permanent magnets

In the rotor 10 According to the embodiment, the opening angles θ _M1 . θ _M2 and θ _M3 the arc shape of the permanent magnets 16 . 17 and 18 the three layers a prescribed relationship. The opening angle θ _M1 . θ _M2 and θ _M3 the arc shape of the permanent magnets 16 . 17 and 18 The first position, the second position and the third position mean the center angles of circular arcs, the approximations to the arc shapes of the permanent magnets 16 . 17 and 18 represent. That is, each of the opening angles θ _M1 . θ _M2 and θ _M3 is an angle that is formed by straight lines that are the center point (focal point) c1 . c2 respectively. c3 a circular arc as an approximation of the arc shape of the permanent magnet 16 . 17 respectively. 18 and the two ends of the permanent magnet 16 . 17 respectively. 18 connect together in its longitudinal direction.

Although in the in 2 shown mode the centers (focal points) c1 . c2 and c3 the arc shape of the permanent magnets 16 . 17 and 18 are spaced apart, a description will first be given of a mode in which the centers (focal points) c the arc shape of the permanent magnets 16 . 17 and 18 as in 3 shown coincide.

As in 3 shown, the distance from the center of rotation O of the rotor core 11 to the center c the arc shape of the permanent magnets 16 . 17 and 18 With R _θ designated. The distance from the center of rotation O of the rotor core 11 to the outer peripheral surface 11a , that is the radius of the rotor core 11 , will with R designated. The number of magnetic poles of the rotor 10 is denoted by n, and 180 ° / n is used with θ _r designated. In the embodiment, n is equal to 8 and θ _r is equal to 22.5 °. The parameter θ _r means half the center angle of a magnetic pole.

Furthermore, a limit distance R0 R0 = R (1 + cos _r) / 2cosθ _r defined. As in 3 shown is a point r that in the distance R0 from the center of rotation O located on the axis (d-axis of the rotor) passing through the center of the rotor core 11 goes, the midpoint between a point r 'on the tangent to the rotor core 11 at the end of the magnetic pole and the point on the outer circumference of the rotor core 11 ,

$${\mathrm{\theta }}_{\text{M}3}\le {\mathrm{\theta }}_{\text{M}1}<{\mathrm{\theta }}_{\text{M}2}\left({\text{wenn R}}_{\mathrm{\theta }}\ge \text{R0}\right).$$

In the rotor 10 According to the embodiment, the opening angles satisfy θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 one or the other of the following relationships: $${\mathrm{\theta }}_{\text{M}3}<{\mathrm{\theta }}_{\text{<figure-callout id="2" label="M" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">M</figure-callout>}2}<{\mathrm{\theta }}_{\text{M}1}\left({\text{if R}}_{\mathrm{\theta }}<\text{R0}\right)$$

$${\mathrm{\theta }}_{\text{M}3}\le {\mathrm{\theta }}_{\text{M}1}<{\mathrm{\theta }}_{\text{M}2}\left({\text{if R}}_{\mathrm{\theta }}\ge \text{R0}\right),$$

Because in the rotor 10 According to the embodiment, the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 the relationship of the above inequality (1) or (2) depending on the position of the center c can satisfy, harmonic components in the waveform of the magnetic flux density distribution, by all permanent magnets 16 . 17 and 18 in the air gap 50 of the motor 1 can be caused to be more reduced, that is, the waveform of the magnetic flux density distribution can be brought closer to a sine wave, than in cases where the opening angles θ _M1 . θ _M2 and θ _M3 have other relationships.

The waveform of in the air gap 50 generated magnetic flux density distribution is a function of the electrical angle of the rotor 10 and its fundamental wave is a sine wave whose period is 360 ° in terms of the electrical angle and 360 ° / (number of pole pairs) in terms of the mechanical angle. The number of pole pairs is equal to half the number n of the magnetic poles and is the same in the embodiment 4 , Because the permanent magnets 16 . 17 and 18 embedded in layers, the magnetic flux density distribution is a stepped waveform as in FIG 4 etc. shown. The proportions of the fundamental sinusoidal wave and harmonic waves of the respective orders of this waveform can be estimated by a frequency analysis calculation such as a Fourier transform. Reduced harmonic components means a state in which the contributions of all harmonic waves to the waveform are small. For example, the contributions of harmonic components can be obtained by using the entire harmonic distortion, "Total Harmonic Distortion ( THD ) ", As an index. The total harmonic distortion is determined as the ratio of the sum of the proportions of all harmonic waves to the proportion of the fundamental wave in the waveform of interest plus the sum of the proportions of all the harmonic waves. The proportion of harmonic components decreases the smaller the total harmonic distortion becomes.

The reason why harmonic components of a magnetic flux density distribution in the air gap 50 can be reduced by the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 satisfy the relation of inequality (1) or (2) can be explained as follows. The larger the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 The larger the longitudinal lengths of the arc shapes of the permanent magnets become 16 . 17 and 18 , and magnetic fluxes, the products of remanence of permanent magnets 16 . 17 and 18 with their cross-sectional areas are getting larger. That is, their contribution to the magnetic flux density distribution in the air gap 50 increases.

The magnetic flux density distribution in the air gap 50 assumes a maximum value or a minimum value when the electrical angle corresponds to a position just opposite to the magnetic pole, namely, when the electrical angle corresponds to the d-axis of the rotor. At this electrical angle carries the of the permanent magnet 16 Magnetic flux emanating from the first position most to the magnetic flux density in the air gap 50 at, and the contribution to the magnetic flux density decreases, the farther the respective permanent magnet is inward, in the order of the permanent magnet 17 (second layer) and the permanent magnet 18 (third layer). On the other hand, the farther the electrical angle from the d-axis of the rotor, the contribution of the permanent magnet gradually increases 17 (second layer). The more the electrical angle is further away from the d-axis direction of the rotor, the contribution of the permanent magnet also increases 18 (third layer).

In the case that R _θ <R0 is satisfied, that is, if the center c the permanent magnet 16 . 17 and 18 is located at a relatively inward position, which is close to the outer periphery of the rotor core 11 are the curvatures of the arc shapes of the permanent magnets 16 . 17 and 18 large and the differences between the curvatures of the respective layers are also large. In this case, because of the permanent magnet 16 the first layer has a particularly large curvature and with the outer circumference of the rotor core 11 forms a large angle, one from the permanent magnet 16 The magnetic flux flowing out of the first layer hardly generates the magnetic flux density distribution in the air gap 50 contribute. So that the permanent magnet 16 the first layer sufficient for generating the magnetic flux density distribution in the air gap 50 contributes, it is necessary to the opening angle θ _M1 to increase and the amount of the permanent magnet 16 to increase the first layer generated magnetic flux. Further, when the electrical angle is removed from the d-axis direction of the rotor, the permanent magnet tends 17 (second Position) and the permanent magnet 18 (third layer) to, stronger for forming the magnetic flux density distribution in the air gap 50 contribute. Thus, the waveform approaches the magnetic flux density distribution in the air gap 50 in the case that the opening angle θ _M1 . θ _M2 and θ _M3 in the order (θ _M3 <θ _M2 <θ _M1 ), that is, as the position of the permanent magnet in the order of the first layer, the second layer, and the third layer inwardly decreases, reduces to a sine wave, so that their Value gradually decreases as the position moves away from the d axis of the rotor.

On the other hand, in the case that R _θ ≥ R0 is satisfied, that is, if the center c the permanent magnets 16 . 17 and 18 is located at a relative far outward position, from the outer periphery of the rotor core 11 far away, the curvatures of the arc shapes of the permanent magnets 16 . 17 and 18 small, and the differences between the curvatures of the respective layers are also small. In this case, wear the permanent magnet 17 (second layer) and the permanent magnet 18 (Third layer), the more the electrical angle of the d-axis of the rotor, the less the generation of the magnetic flux density distribution in the air gap 50 at. When the opening angle θ _M2 and θ _M3 of the permanent magnet 17 (second layer) and the permanent magnet 18 (Third layer) are small, the magnetic flux density decreases sharply when the electrical angle by a certain amount from the d-axis of the rotor.

With a sine wave, however, the variation rate of its value is smallest in the vicinity of the maximum value and the minimum value. To such a behavior with a magnetic flux density distribution in the air gap 50 To realize, it is necessary to avoid that the magnetic flux density in the vicinity of the d-axis of the rotor changes greatly. This can be achieved by passing through the permanent magnet 17 (Second layer) generated magnetic flux, which contributes to the formation of a magnetic flux density distribution at an electrical angle, which is spaced by a certain angle from the d-axis of the rotor is set greater than the magnetic flux from the permanent magnet 16 (first layer) is generated. That is, a setting θ _M1 < θ _M2 should be respected. On the other hand, in a sine wave, the variation rate of its value is greatest in the vicinity of its inflection point, which is midway between a maximum position and a minimum position. To such a behavior with a magnetic flux density distribution in the air gap 50 It is necessary to realize this through the permanent magnet 18 (Third layer) generated magnetic flux, which contributes more to generating the magnetic flux density distribution at an electrical angle in the vicinity of the q 'axis, which is spaced 90 ° from the d-axis of the rotor, is set smaller than that by the permanent magnet 17 (second layer) generated magnetic flux. That is, a setting θ _M3 < θ _M2 should be respected.

While with the permanent magnet 16 (first layer) and the permanent magnet 18 (Third layer) on one side in the thickness direction (ie, the radial direction of the rotor core 11 ) no permanent magnet is present, are the permanent magnets 16 and 18 on both sides, in the thickness direction, of the permanent magnet 17 (second layer) arranged. Thus, one of the second permanent magnet 17 (second layer) outgoing magnetic flux both on the permanent magnet 17 outgoing path to the air gap 50 as well as on the return path to the permanentmagent 17 through a narrow magnetic path in the rotor core 11 to step. Thus, one of the second permanent magnet must 17 (second layer) outgoing magnetic flux sufficient to generate the magnetic flux density distribution in the air gap 50 contributes, the opening angle θ _M2 be set large.
In the event that the center c the permanent magnets 16 . 17 and 18 close to the outer periphery of the rotor core 11 is, as in the case of R _θ <R0 described above, the assurance of the required contribution of the permanent magnet 16 (first layer) for generating the magnetic flux density distribution in the air gap 50 , by setting a large opening angle θ _M1 , Priority given to ensuring the contribution of the permanent magnet 17 (second layer) for generating the magnetic flux density distribution in the air gap 50 , by setting a large opening angle θ _M2 ,

As described above, the opening angles θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 in the case that the relation R _θ ≥ R0 is satisfied and hence the center c the permanent magnets 16 . 17 and 18 from the outer circumference of the rotor core 11 away, set so that the inequality relationship ( 2 ), that is, θ _M3 ≤ θ _M1 <θ _M2 , thereby reducing the contribution of the permanent magnet 17 (second layer) for generating the magnetic flux density distribution in the loss gap 50 is relatively large. As a result, in the waveform of the magnetic flux density distribution, first, the magnetic flux density does not vary much as the electrical angle is away from the d axis direction of the rotor (d'axis), and thereafter, the magnetic flux density greatly varies as the electrical angle is further away from the direction of the d-axis of the rotor (d'-axis) and approaches the direction of the q'-axis; the waveform of the magnetic flux density distribution thus behaves like a sine wave.

In particular, adjusting the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 such that the inequality (2) is satisfied, in the case that the relationship R _θ ≥ R / cos θ _{r is} satisfied, with regard to the effect of reducing harmonic waves of the magnetic flux density distribution in the air gap 50 think. A position where the relation R _θ ≥ R / cos θ _{r is} satisfied corresponds to that in FIG 3 Point shown r 'on the tangent to the rotor core 11 at the end of the magnetic pole.

As described above, it is possible to use harmonic components of the air gap 50 to reduce the magnetic flux density distribution generated and to make its waveform closer to a sine wave by adjusting the aperture angles θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 of the respective layers satisfy the relation of inequality (1) or (2), depending on the position of their center c , Harmonic components of the magnetic flux density distribution are a cause for the generation of torque ripple in the motor 1 and cause vibrations and noise. Furthermore, harmonic components increase the iron loss of the rotor core 11 , Thus, the reduction of harmonic components of the magnetic flux density distribution makes it possible to reduce torque ripple and iron loss, and vibration and noise of the motor 1 to suppress. For example, as described below as a simulation result, it is possible to reduce the harmonic components of the magnetic flux density distribution to such an extent that the total harmonic distortion becomes less than or equal to 23%.

Whether R _θ <R0 is satisfied, ie the center c the arc shape of the permanent magnets 16 . 17 and 18 is located at a relative far inner position, so that the opening angle θ _M1 . θ _M2 and θ _M3 satisfy the relation of inequality (1), or R _θ ≥ R0 is satisfied, that is, the center c the arc shape of the permanent magnets 16 . 17 and 18 is located at a relatively far outward position, so that the opening angle θ _M1 . θ _M2 . θ _M3 can satisfy the relationship of inequality (2), depending on the specific requirements of the engine 1 to be selected.
In the event that the center c the arc shape of the permanent magnets 16 . 17 and 18 is arranged outside, as in the case that R _θ ≥ R0, becomes the reluctance torque of the motor 1 large. In the range of R _θ ≥ R0, the reluctance torque increases as a function of the distance R _θ from the center c the arc shape of the permanent magnets 16 . 17 and 18 a maximum value. Until the maximum value is reached by the center c wandering outwards, the radii of curvature of the permanent magnets increase 16 . 17 and 18 and make the magnetic paths of the permanent magnets 16 . 17 and 18 more suitable to run along the shape of a q-axis magnetic flux, and thereby the reluctance torque is increased.
In the case that R _θ ≥ R / cos θ _{r is} satisfied, the reluctance torque becomes particularly large. However, in the case that is the center c is further out, the maximum value is exceeded, and the reluctance torque will decrease conversely. Thus, it is generally preferred that its relationship R _θ <R (3-2 cosθ _r ) / cosθ _r or even a relation R _θ <R (2-cosθ _r ) / cosθ _{r is} satisfied. A position where R _θ <R (3-2 cosθ _r ) / cosθ _{r is} satisfied and a position where R _θ <R (2-cosθ _r ) / cosθ _{r is} satisfied are positions that are from the outer periphery of the rotor core 11 three times or twice the distance of the in 3 shown point r '(ie the point on the tangent to the rotor core 11 at each end of the magnetic pole) are removed.

In the case that the relation R _θ <R0 is satisfied, it is preferable that a relation R _θ > 0.8R is satisfied to sufficiently ensure that the arc-shaped permanent magnets 16 . 17 and 18 leading to the inner peripheral side of the rotor core 11 are convex, in the direction from the outer peripheral side to the inner peripheral side of the rotor core 11 are arranged in layers. It is even preferable that a relation R _θ > R is satisfied, the center c the arc shape of the permanent magnets 16 . 17 and 18 outside the rotor core 11 is arranged.

The above description concerns the case that the centers c the permanent magnets 16 . 17 and 18 coincide. However, the reluctance torque can be increased by the respective centers c1 . c2 and c3 the arc shape of the permanent magnet 16 . 17 and 18 of the three layers differ from each other. In the event that the centers c1 . c2 and c3 the arc shape of the permanent magnet 16 . 17 and 18 differ, the relation of inequality (1) or (2) can be applied after the position of an average center c the centers c1 . c2 and c3 the arc shape of the permanent magnet 16 . 17 and 18 of the three layers is determined by calculating a distance R _θ of the center c from the center of rotation O of the rotor core 11 and setting a threshold distance R0 , Similarly, the position of an average center c the centers c1 . c2 and c3 and a margin distance R0 for the relationship between the remanences Br1 . Br2 and Br3 the inequalities (4) and (5) described later.

The above description relates to the case where the permanent magnets 16 . 17 and 18 arranged in three layers and the relationship between their opening angles θ _M1 . θ _M2 and θ _M3 is set. However, as described above, there is no particular limitation on the number of layers of the permanent magnets. as long as it is greater than, or equal to two. In the event that permanent magnets are arranged in four or more layers, it is sufficient that the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 the first to third layers from the outer peripheral side of the rotor core 11 satisfy inequality (1) or (2), depending on the position of the center c , Harmonic components of the magnetic flux density distribution in the air gap 50 can be sufficiently reduced even if any opening angles are set for the fourth and further inside permanent magnets. This is because the contribution to the magnetic flux density distribution in the air gap 50 the smaller the position of the permanent magnet moves inward, and the inner permanent magnets have no great influence on the waveform of the magnetic flux density distribution, no matter how their aperture angles are set, as long as the aperture angles of the outer permanent magnet satisfy the prescribed relationship.

unabhängig von den Positionen der Zentren der Bogenformen der jeweiligen Permanentmagneten.On the other hand, in the case where the number of layers of permanent magnets is two, harmonic components of those in the air gap may be used 50 generated magnetic flux density distribution can be reduced when the opening angle θ _M1 and θ _M2 the arc shapes of the permanent magnets of the first and second layers are set so as to satisfy the following inequality (3), but to a lesser degree than in the case where the aperture angles θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 the three outer layers are set to satisfy the above-described relationship. In the case where the number of layers of the permanent magnets is two, their opening angles become θ _M1 and θ _M2 adjusted to satisfy the following inequality (3): $${\mathrm{<figure-callout\; id="2"\; label="\theta \; M"\; filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\theta \; </figure-callout>}}_{\text{M}}<{\mathrm{\theta }}_{\text{<figure-callout id="1" label="M" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">M</figure-callout>}1}$$

regardless of the positions of the centers of the arc shapes of the respective permanent magnets.

In the rotor 10 According to the embodiment, the outer peripheral surface 11a of the rotor core 11 with dents 1 1b educated. The dents 11b also play a role in reducing the harmonic components of the magnetic flux density distribution in the air gap 50 , This is because the saturation of the magnetic flux density, which leads to an increase in the harmonic components, by increasing the width of the air gap 50 (ie the distance between the rotor 10 and the stator 30 ) can be suppressed. However, the education of dents increases 11b the equivalent air gap width and can reduce the torque. In the rotor 10 According to the embodiment, the outer peripheral surface 11a of the rotor core 11 to further reduce the harmonic components with the dents 11b be formed, so in addition to the reduction due to the effect of the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 which are set to satisfy inequality (1) or (2). Alternatively, the dents 11b may be omitted to avoid a decrease in torque because the harmonic components can be effectively reduced by satisfying the inequality (1) or (2).

( 2 Remanences (residual magnetic flux densities) of the permanent magnets of each of the permanent magnets 16 . 17 and 18 generated magnetic flux is given by the product of the remanence and the cross-sectional area of the permanent magnet. Thus, in the event that the remanences Br1 . Br2 and Br3 the permanent magnet 16 . 17 and 18 are equal, harmonic components of the magnetic flux density distribution in the air gap 50 be reduced by that the opening angle θ _M1 . θ _M2 and θ _M3 , which are the cross-sectional areas of the permanent magnets 16 . 17 and 18 be set to satisfy inequality (1) or (2). Even in the event that the remanences Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 are different from each other, without any relationship to each other, can harmonic components of the magnetic flux density distribution in the air gap 50 by adjusting the opening angle θ _M1 . θ _M2 and θ _M3 so that they satisfy the inequality (1) or (2), smaller than in a case where neither the inequality (1) nor the inequality (2) are satisfied.

Alternatively, harmonic components of the magnetic flux density distribution in the air gap 50 by adjusting the remanences Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 such that they are arranged in the same order as their opening angles θ _M1 . θ _M2 and θ _M3 (Inequality (1) or (2)), instead of the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 to be set to satisfy inequality (1) or (2).
As a further alternative, harmonic components of the magnetic flux density distribution in the air gap 50 be reduced more efficiently than in the case that only the measure of adjusting the opening angle θ _M1 . θ _M2 and θ _M3 so that they fulfill the inequality (1) or (2), is taken by the remanence Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 be set so that they are in the same order as the opening angle θ _M1 . θ _M2 and θ _M3 (Inequality (1) or (2)), in addition to the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 be set to satisfy inequality (1) or (2).

$$\text{Br}3\le \text{Br}1<\text{Br}2\left({\text{wenn R}}_{\mathrm{\theta }}\ge \text{R0}\right).$$

That is, the remanences Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 the first, second and third positions are set to satisfy the following inequality (4) or (5) instead of or in addition to the adjustment of the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 such that they fulfill the inequality (1) or (2): $$\text{<figure-callout id="3" label="br" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}3<\text{<figure-callout id="2" label="br" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}2<\text{br}1\left({\text{if R}}_{\mathrm{\theta }}<\text{R0}\right)$$

$$\text{br}3\le \text{br}1<\text{br}2\left({\text{if R}}_{\mathrm{\theta }}\ge \text{R0}\right),$$

In the event that the remanences Br1 . Br2 and Br3 be set to match the relation of inequality (4) or (5) according to the position of the (average) center c the arc shape of the permanent magnets 16 . 17 and 18 meet the particular situation, behaves when the electrical angle θ changes, the waveform of the magnetic flux density distribution in the air gap 50 in the same way as in the case that opening angle θ _M1 . θ _M2 and θ _M3 be set to satisfy the inequality (1) or (2). Thus, harmonic components of the waveform of the magnetic flux density distribution in the air gap 50 can be reduced, and the waveform can thereby be made closer to a sine wave. As a result, it becomes possible in the engine 1 To reduce the torque ripple and iron loss, suppress vibration and noise, and increase the efficiency of the engine.

So far, the mode has been described, in which the permanent magnets 16 . 17 and 18 arranged in three layers and the relationship between their remanences Br1 . Br2 and Br3 is set. In the event that permanent magnets are arranged in four or more layers, it is sufficient that the remanences Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 the first to third layers from the outer peripheral side of the rotor core 11 depending on the position of the (average) center c satisfy the inequality (4) or (5). Because the contribution of the fourth and further inner permanent magnet to the formation of the magnetic flux density distribution in the air gap 50 is small, harmonic components of the waveform of the magnetic flux density distribution in the air gap 50 are sufficiently reduced even if the remanences of the fourth and further inner permanent magnets take any value.

Unabhängig von den Positionen der Zentren der Bogenformen der jeweiligen Permanentmagnete.On the other hand, in the case that the number of layers of permanent magnets is two, harmonic components of the magnetic flux density distribution in the air gap can be made 50 be reduced if the remanence Br1 and Br2 the permanent magnets of the first and second layers are set so as to satisfy the relation of the following inequality (6), though to a lesser degree than in the case where the remanences Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 the three outer layers are set to satisfy the above-described relationship. In the case that the number of layers of permanent magnets is two, their remanences become Br1 and Br2 adjusted so that the following inequality (6) is satisfied: $$\text{<figure-callout id="2" label="br" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">br</figure-callout>}2<\text{<figure-callout id="1" label="br" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">br</figure-callout>}1$$

Regardless of the positions of the centers of the arc shapes of the respective permanent magnets.

The remanences Br1 and Br2 are set to satisfy the inequality (6) instead of the opening angles θ _M1 and θ _M2 To set the permanent magnets of the two layers so that meet the inequality (3). Alternatively, the remanences Br1 and Br2 adjusted to satisfy inequality (6), in addition to adjusting the opening angle θ _M1 and θ _M2 the permanent magnet of the two layers so that they meet the inequality (3).

The absolute values of the remanences Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 (or the remanences Br1 and Br2 ) are not particularly specified as long as they satisfy the inequality (4) or (5) or inequality (6). However, it is all the easier, the desired torque of the engine 1 even if the thickness (ie, the dimension between the outer peripheral side edge and the inner peripheral side edge of the arc shape) of each of the permanent magnets 16 . 17 and 18 is reduced, the more the remanences Br1 . Br2 and Br3 the permanent magnets 16 . 17 and 18 increase. In the case that the thickness of each of the permanent magnets 16 . 17 and 18 is decreased, the q-axis magnetic flux path becomes wider, whereby the reluctance torque of the motor 1 can be increased. As a result, a large output torque can be obtained in such a manner that the reluctance torque adds to the magnetic torque.

As described above, the permanent magnets include 16 . 17 and 18 in the embodiment, metal magnets. As described in Patent Document 1, although conventionally bonded magnets are widely used as permanent magnets in ordinary rotors with embedded permanent magnets, metal magnets have a higher remanence than bonded magnets. Thus, the use of metal magnets allows the permanent magnets 16 . 17 and 18 to make thinner and increase the reluctance torque while maintaining a large magnetic torque. In particular, the use of metal magnets effectively enables the reluctance torque in deep field weakening regions with high rotor rotation 10 to increase, and thus a high-torque high-torque motor 1 to realize.

Focal point positions of the permanent magnets

In the rotor 10 according to the in 2 the embodiment shown are the focal points of the permanent magnets 16 . 17 and 18 the three layers, so the centers c1 . c2 and c3 their shapes, which are shaped approximately like circular arcs, at different points of the d axis of the rotor. More precisely, the center c1 of the permanent magnet 16 (first location), the center c2 of the permanent magnet 17 (second location) and the center c3 of the permanent magnet 18 (Third layer) are in this order at different positions along the d-axis of the rotor from the outer peripheral side to the inner peripheral side of the rotor core 11 arranged.

Because the centers (focal points) c1 . c2 and c3 the permanent magnets 16 . 17 and 18 of the three layers deviate from each other in this order, the interlayer distances vary L1 respectively. L2 between each pair of adjacent ones of the permanent magnets 16 . 17 and 18 along the longitudinal direction of their arch forms. Specifically, the liner distance L1 respectively. L2 is large at the side near the d-axis of the rotor (d'-axis) and decreases as the position progresses away from the d-axis of the rotor, and closer to the q'-axis.

Because, as described above, the interlayer distances L1 respectively. L2 between the permanent magnets 16 . 17 and 18 vary in their longitudinal direction, some difference occurs between magnetic flux densities of the magnetic flux path of the d-axis of the rotor and the magnetic flux path of the q-axis, and thus, in the rotor core 11 occurring reluctance torque can be made large.
If there is also a position where the gap between each pair of adjacent ones of the permanent magnets 16 . 17 and 18 decreases rapidly, a local concentration of magnetic flux occurs in the rotor core 11 on, causing irreversible flux losses of the permanent magnets 16 . 17 and 18 be favored. However, in the rotor 10 According to the embodiment, such local concentrations of magnetic flux are not favored because the interlayer distances L1 and L2 between the permanent magnets 16 . 17 and 18 only gradually along the arc shapes of the permanent magnets 16 . 17 and 18 vary.

While in the embodiment all centers c1 . c2 and c3 the permanent magnets 16 . 17 and 18 of the three layers lying on the d axis of the rotor, the centers can c1 . c2 and c3 also be spaced from the d axis of the rotor as long as they are in this order from the outer peripheral side to the inner peripheral side of the rotor core 11 are arranged. Even in the case that the permanent magnets 16 . 17 and 18 Of the three layers are not formed approximately as circular arcs, it is appropriate to set the focal points (centers) of circular arcs or ellipses as approximations of their arc shapes at positions that differ in the manner described above.

So far, the mode has been described, in which the permanent magnets 16 . 17 and 18 arranged in three layers and their focal points c1 . c2 and c3 are arranged differently from each other. However, in the case where the number of layers of permanent magnets is equal to two, it is appropriate to use the focal point c1 the outermost (ie, the first layer) permanent magnet 16 in the radial direction outside the focal point c2 of the second-position permanent magnet 17 to lay. In the case where the number of layers of permanent magnets is four or more, when the focal points of the outermost and second outermost permanent magnets or the outermost, second outermost and third outermost permanent magnets may be in the same order as the permanent magnets from the outer peripheral side to the inner peripheral side of the rotor core 11 are set so as to leave gaps therebetween, the effect of torque ripple reduction and reluctance torque increase may be sufficient even if the focal points of the inner fourth and further permanent magnets are set at arbitrary positions, because the fourth and further inner permanent magnets only a small contribution to the magnetic flux density distribution in the air gap 50 Afford. These effects can be increased by setting the focal points of the fourth and further inner permanent magnets such that the focal points of the permanent magnets are closer to the inner peripheral side of the rotor core 11 are set, the further inside the respective permanent magnet is arranged.

Other parameters regarding shapes, arrangement, etc. of the permanent magnets - thickness of the permanent magnets

There are no particular restrictions on specific dimensions of the permanent magnets 16 . 17 and 18 the three layers. However, it is preferable that the thicknesses T1 . T2 and T3 (Each dimension between the edge on the outer peripheral side of the rotor core 11 and the edge on the inner peripheral side) of the permanent magnets 16 . 17 and 18 the first, second and third layers satisfy a relationship T1 ≦ T2 ≦ T3. It is more preferable if they satisfy a relationship T1 ≦ T2 <T3 or T1 <T2 <T3.

In the case that the number of layers of permanent magnets is two, it is preferable that the thickness T1 of the outer permanent magnet and the thickness T2 of the inner permanent magnet satisfy the relationship T1 ≦ T2, or more preferably, T1 <T2. In the case that the number of layers of permanent magnets is four or more, it suffices if the thicknesses T1 . T2 and T3 of the outermost, second outermost and third outermost permanent magnets satisfies the relation T1 ≦ T2 ≦ T3, T1 ≦ T2 <T3 or T1 <T2 <T3. As far as inner permanent magnets are concerned, it is expedient if their thicknesses are greater, the further inward they are arranged.

As described above, in the rotor 10 the phenomenon occur that magnetic fluxes are local between the permanent magnets 16 . 17 and 18 concentrate and irreversible flux losses of the permanent magnets 16 . 17 and 18 cause. Such local concentrations of the magnetic flux are particularly liable to occur in a radially inner portion of the rotor core 11 on. It is therefore possible to make the occurrence of irreversible flow losses less likely by increasing the thicknesses of permanent magnets in radially inner layers.

- Interlayer distances of the permanent magnets

In the case that the permanent magnets 16 . 17 and 18 arranged in three layers, the distance can be L1 between the first-layer permanent magnet 16 and the second-layer permanent magnet 17 equal to the distance L2 between the second-layer permanent magnet 17 and the third-layer permanent magnet 18 but it is preferable that the distance L1 is greater than the distance L2 (L1> L2). This is because the interlayer distances L1 and L2 by the difference between the center angles θ1 and θ2 of the first-layer permanent magnet 16 and the second-layer permanent magnet 17 or the difference between the center angles θ2 and θ3 of the second-layer permanent magnet 17 and the third-layer permanent magnet 18 (please refer 3 ) are determined. As will be described later, the center angles correspond θ1 . θ2 and θ3 close to the mechanical angles α . β respectively. γ of steps of a stepwise magnetic flux density distribution waveform. To the waveform of a in the air gap 50 It is preferable that the difference between the center angles be made closer to a sine wave as formed stepwise magnetic flux density distribution θ1 and θ2 is greater than the difference between the center angles θ2 and θ3 , In this case, the relationship is L1> L2.

As described above, in the case that the positions of the centers (focal points) vary c1 . c2 and c3 the permanent magnets 16 . 17 and 18 the three layers deviate from each other, the spacing between the layers L1 and L2 between the permanent magnets 16 . 17 and 18 in the longitudinal direction of the permanent magnets 16 . 17 and 18 , Even in this case, it is preferable that the respective average values of the distances L1 and L2 satisfy the relationship L1> L2. In the case where there are four or more permanent magnets, it is sufficient that the inter-gap distances between the outermost, second-external and third-outermost permanent magnets satisfy the relationship of L1> L2. As far as inner permanent magnets are concerned, it is desirable that the spacing of the spacers between adjacent permanent magnets decreases the farther their position is inward.

- Magnetization directions of the permanent magnets

It is preferred that the permanent magnets 16 . 17 and 18 Have magnetization directions of radial alignment, so that the magnetization directions of each of the permanent magnets 16 . 17 and 18 lie on radial lines that extend from its focal point. In addition, it is preferable that the focal point of the magnetization directions of each of the permanent magnets 16 . 17 and 18 with the focal point (center) c1 . c2 respectively. c3 its arch shape coincides. The measures allow harmonic components of the waveform of the magnetic flux density distribution in the air gap 50 decrease while the output torque of the motor 1 stays big.

In addition, the demagnetization resistance of each magnet is increased because magnetic magnetization directions of radial alignment intersect with inverse magnetic fields acting on the magnets originating from magnetic fluxes of the coils at an angle close to 90 °. The magnetization directions of the permanent magnets 16 . 17 and 18 can be adjusted in manufacture by controlling the direction of crystallization.

[Determination of Waveform of Magnetic Flux Density Distribution on the Basis of Permanent Magnet Configuration]

As described above, in the rotor 10 According to the embodiment, the sets of configuration parameters of the permanent magnets 16 . 17 and 18 such as their shapes, their arrangement and the remanences, from the viewpoint of reducing the harmonic components of the waveform of the magnetic flux density distribution in the air gap 50 set. In order to effectively reduce the harmonic components of the magnetic flux density distribution waveform, it is important to know the correlation between the sets of configuration parameters of the permanent magnets 16 . 17 and 18 and the waveform of the magnetic flux density distribution in addition to appropriately setting the sets of configuration parameters of the permanent magnets 16 . 17 and 18 to evaluate correctly.

To a configuration of the rotor 10 to determine which allows harmonic components of the waveform of the magnetic flux density distribution in the air gap 50 by taking into account the correlation between the sets of configuration parameters of the permanent magnets 16 . 17 and 18 and the magnetic flux density distribution waveform, for example, one may first assume, as a target waveform, a magnetic flux density distribution waveform in which harmonic components are reduced to predetermined levels.

Thereafter, the sets of configuration parameters of the permanent magnets become 16 . 17 and 18 the respective layers, such as the opening angle θ _M1 . θ _M2 and θ _M3 the bow forms and the positions of the centers c1 . c2 and c3 set a waveform through the permanent magnets 16 . 17 and 18 with these sets of configuration parameters in the air gap 50 is simulated and checks whether the waveform obtained by the simulation is a reproduction of the assumed target waveform. If the obtained waveform is not a suitable reproduction of the assumed target waveform, the sets of the configuration parameters of the permanent magnets become 16 . 17 and 18 adjusted so that the simulated waveform becomes closer to the target waveform.

A magnetic flux density distribution at which harmonic components are effectively reduced can be obtained by using the sets of configuration parameters of the permanent magnets 16 . 17 and 18 are correlated with the magnetic flux density distribution and the sets of configuration parameters are set to specific values, and their interrelations are adjusted by performing simulations such that the resulting waveform is closer to the target waveform.

For example, a simulation can be performed by an electromagnetic field analysis using a finite element method (FEM). In a simulation, a magnetic flux density distribution in the air gap 50 estimated, wherein a "leakage" of magnetic fluxes of the permanent magnets 16 . 17 and 18 (Shorting, in the rotor core 11 , of magnetic flux flowing through the bridges 21 taking into account).

In estimating the sets of configuration parameters of the permanent magnets 16 . 17 and 18 by simulations, it is first necessary, as a target waveform, a waveform of the magnetic flux density distribution in the air gap 50 adjust. As in 4 shown is the magnetic flux density distribution in the air gap 50 a periodic function that decreases and increases repeatedly, where one cycle is 360 ° as an electrical angle and 360 ° / (number of pole pairs) as a mechanical angle (where Example 90 ° are discussed). The periodic function increases and decreases in threefold graded form, which corresponds to the fact that the permanent magnets 16 . 17 and 18 have a three-layered structure and in the rotor 10 are embedded.

In the following description, in the magnetic flux density distribution, the magnetic flux density Bg is in the air gap 50 normalized on the vertical axis so that it has a maximum amplitude of "1". In the stepped waveform, the angles corresponding to the steps are represented by θ = α, β and γ (from above), respectively, and the heights of the steps are represented by Bg = 1, A, B and 0, respectively (from above).

The magnetic flux density distribution waveform in the gap is varied in various ways by changing the combination of values of the waveform parameters α . β . γ . A and B which determine the magnetic flux density distribution waveform. Portions of the fundamental wave and harmonic waves of the respective orders can be estimated by performing a Fourier transform on the obtained waveform. A value of the total harmonic distortion (THD), ie the ratio of the sum of the proportions of all harmonic waves to the proportion of the fundamental wave plus the sum of the proportions of all harmonic waves, can be calculated.
An appropriate combination of such values of the waveform parameters α . β . γ . A and B a search is made for the resulting THD value to become a minimum value or less than or equal to a predetermined upper limit value. This can be done in such a way that, as will be described later in Examples, a combination of values of the waveform parameters α . β . γ . A and B which gives a relatively small THD value, is coarsely found, and mapped by calculating THD values, and thereby α . β, γ . A and B be varied around this combination. A minimum or a range in which the THD value is less than or equal to the predetermined upper limit is determined, and the target waveform is set as the waveform corresponding to the minimum and the range, respectively.

After that, a model of the rotor 10 created by adding values for the sets of configuration parameters (shapes, arrangements, remanences, etc.) of the permanent magnets 16 . 17 and 18 be accepted. As in 3 show examples of the sets of configuration parameters of the permanent magnets 16 . 17 and 18 the center angle θ1 . θ2 and θ3 , the opening angle θ _M1 . θ _M2 and θ _M3 , the positions of the centers c1 . c2 and c3 (in the mode of 3 they fall to the center c together), the radii R1 . R2 and R3 and the thicknesses T1 . T2 and T3 (in the mode of 3 they are all identical).

A waveform of the magnetic flux density distribution in the air gap 50 is for the model of the rotor thus created 10 estimated by performing a simulation by electromagnetic field analysis. Then, it is judged whether or not one of the assumed target waveforms has been obtained by comparing the estimated waveform with the target waveform. This can be done by comparing THD values of the waveform obtained by the simulation and the target waveform. If no waveform is obtained that is closer to the target waveform, a simulation is performed again after the sets of configuration parameters of the permanent magnets 16 . 17 and 18 has been adjusted, and it is checked if the new waveform is closer to the target waveform. Values of the sets of configuration parameters of the permanent magnets 16 . 17 and 18 which give a magnetic flux density distribution waveform close to the target waveform can be determined in this way.

In the target waveform, the step angles α, β and γ as far as they correspond to mechanical angles approximately coincide with the center angles θ1, θ2 and θ3 of the permanent magnets 16 . 17 and 18 together, that is, the angles from the d-axis of the rotor to the ends, in the longitudinal direction, of the outer peripheral side edges of the permanent magnets 16 . 17 respectively. 18 ; and the differences between the step heights 1 , A and B correspond approximately to the opening angles θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 respectively. 18 , Using values of these parameters as a guide, an initial arrangement of the permanent magnets becomes 16 . 17 and 18 set for use for a simulation and the sets of configuration parameters of the permanent magnets 16 . 17 and 18 are adjusted based on the initial arrangement.

By setting the target waveform to be close to a sine wave and estimating sets of configuration parameters of the permanent magnets 16 . 17 and 18 thus, as described above, reproducing the target waveform as will be described later in Examples, it is found that the relationship between the opening angles θ _M1 . θ _M2 and θ _M3 the permanent magnets 16 . 17 and 18 which is able to reproduce the target waveform, depending on the position of the center c , That is, one A sine wave near target waveform can be adjusted by adjusting the opening angle θ _M1 . θ _M2 and θ _M3 such that the relationship of the above inequality (1) or (2) is satisfied.

Harmonic components of a magnetic flux density distribution can be effectively reduced by taking values of the sets of configuration parameters of the permanent magnets 16 . 17 and 18 appropriately determined, a waveform of the magnetic flux density distribution in the air gap 50 by a simulation on the basis of the thus determined values of the sets of the configuration parameters of the permanent magnets 16 . 17 and 18 and the estimated waveform in setting the values of the sets of configuration parameters of the permanent magnets 16 . 17 and 18 is shown. In addition, even the influence of those parameters whose correlation with the magnetic flux density distribution is analytically difficult to formulate on the magnetic flux density distribution can be determined by taking the relationship between the sets of configuration parameters of the permanent magnets 16 . 17 and 18 and the magnetic flux density distribution is determined by means of a simulation.

However, it is possible to analytically determine the relationship between the sets of configuration parameters of the permanent magnets 16 . 17 and 18 and to determine the magnetic flux density distribution. For example, the sets of configuration parameters of the permanent magnets 16 . 17 and 18 be analytically estimated by a magnetic equivalent circuit with the permanent magnets 16 . 17 and 18 of three layers and the air gap 50 and the equations for closed magnetic paths are solved. In the magnetic equivalent circuit, the aperture angles are θ _M1 . θ _M2 and θ _M3 in the magnetic resistances of the permanent magnets 16 . 17 and 18 included, and the center angle θ1 . θ2 and θ3 are in the magnetic resistance of the air gap 50 included.

$$\text{B}2=\mathrm{\varphi }2\text{/}\left\{\text{R}\cdot \left(\mathrm{\theta }2-\mathrm{\theta }1\right)\cdot \text{L}\right\},$$

$$\text{B}3=\mathrm{\varphi }3\text{/}\left\{\text{R}\cdot \left(\mathrm{\theta }3-\mathrm{\theta }2\right)\cdot \text{L}\right\},$$

wobei θ1, θ2 und θ3 die Zentrumswinkel der Permanentmagnete 16, 17 und 18 der ersten, zweiten bzw. dritten Lage sind, R der Radius des Rotorkerns 11 ist und L die Dicke des Rotorkerns 11 ist (d. h. seine Dimension in der Richtung senkrecht zur Papierebene in 3).In Patent Document 1, the entire magnetic fluxes φ generated by the respective permanent magnet layers are formulated in claim 7, etc., and a magnetic flux density distribution close to a sine wave is obtained by using the total magnetic fluxes φ of the permanent magnets as a guide. However, it's about the waveform in the air gap 50 To correctly determine the formed magnetic flux density distribution, the contributions of magnetic fluxes of the permanent magnets 16 . 17 and 18 in the form of magnetic flux densities B , to take into account instead of the total magnetic fluxes φ.
When the total magnetic fluxes of the permanent magnets 16 . 17 and 18 are equal to φ1, φ2 and φ3, are the magnetic flux densities B1 . B2 respectively. B3 given by: $$\text{<figure-callout id="1" label="B" filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png" state="{{state}}">B</figure-callout>}1=\mathrm{<figure-callout\; id="1"\; label="\phi "\; filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png"\; state="\{\{state\}\}">\phi </figure-callout>}1\text{/}\left(\text{R}\cdot \mathrm{<figure-callout\; id="1"\; label="\theta "\; filenames="DE102019110013A1\_0031.png,DE102019110013A1\_0032.png"\; state="\{\{state\}\}">\theta </figure-callout>}1\cdot \text{L}\right).$$

$$\text{<figure-callout id="2" label="B" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">B</figure-callout>}2=\mathrm{<figure-callout\; id="2"\; label="\phi "\; filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\phi </figure-callout>}2\text{/}\left\{\text{R}\cdot \left(\mathrm{\theta }2-\mathrm{\theta }1\right)\cdot \text{L}\right\}.$$

$$\text{<figure-callout id="3" label="B" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">B</figure-callout>}3=\mathrm{<figure-callout\; id="3"\; label="\phi "\; filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png"\; state="\{\{state\}\}">\phi </figure-callout>}3\text{/}\left\{\text{R}\cdot \left(\mathrm{\theta }3-\mathrm{\theta }2\right)\cdot \text{L}\right\}.$$

in which θ1 . θ2 and θ3 the center angle of the permanent magnets 16 . 17 and 18 the first, second and third positions, respectively, R the radius of the rotor core 11 is and L the thickness of the rotor core 11 is (ie its dimension in the direction perpendicular to the paper plane in 3 ).

Examples

The present invention will be described more specifically below by way of examples.

Relationship between the waveform of the magnetic flux density distribution and sets of configuration parameters of the permanent magnets

In the rotor 10 According to one embodiment of the present invention, harmonic components of the waveform in the air gap become 50 reduces the magnetic flux density distribution produced by arranging the arcuate permanent magnets in multiple layers and determining the interlayer relationships between the sets of permanent magnet configuration parameters, such as the opening angles. In the following it will be described how the relationships between the waveform of the magnetic flux density distribution and the sets of configuration parameters of the permanent magnets are examined by assuming a target waveform close to one Sine wave, and the sets of configuration parameters of the permanent magnets are explained, which are adapted to generate a magnetic flux density distribution, which reproduces the target waveform.

Specify the target waveform

As described above, in the case that the permanent magnets take 16 . 17 and 18 the three layers in the rotor core 11 embedded, the waveform of the magnetic flux density distribution to a three-stage shape. Thus, an initial waveform as in 4 is assumed to be a stepped waveform that is to some extent near a sine wave (fundamental wave). In this waveform are the waveform parameters α . β . γ . A and B , which determine the waveform, set as 35 °, 57 °, 79 °, 0.73 and 0.39, respectively.

Then the parameters α . β . γ . A and B varies in the initial waveform around the above values. The total harmonic distortion (THD values) are estimated for the obtained waveforms. Although this can be done by simultaneously varying all the parameters, in this example the parameters are varied in pairs to simplify the visualization of the results.

Each of the 5 to 7 shows how the THD values behave when two parameters are varied, along with typical waveforms. 5 to 7 show how the THD values behave when pairs of parameters, namely α and β, α and γ respectively A and B be varied.

In each of the 5 to 7 For example, the values of the two waveform parameters used in the initial waveform are located near a range where the THD has a minimum. Thus, it is confirmed that the values of the pair of waveform parameters used in the initial waveform are suitable as values to produce a stepped waveform close to a sine wave. It will also be appreciated that if any one of the waveform parameters deviates from the range in which the THD has a minimum, the THD value increases and the waveform is distorted to be very different from a sine wave.

• α: 25° bis 45°
• β: 55° bis 65°
• γ: 75° bis 85°
• A: 0,58 bis 0,78
• B: 0,25 bis 0,45

At the results of 5 to 7 It can be seen that the THD becomes small and a waveform close to a sine wave can be obtained when the waveform-determining parameters move within the following suitable ranges:

• α: 25 ° to 45 °
• β: 55 ° to 65 °
• γ: 75 ° to 85 °
• A: 0.58 to 0.78
• B: 0.25 to 0.45

Sets of configuration parameters of the permanent magnets that yield the target waveform

Thereafter, values for sets of the configuration parameters of the permanent magnets which give a waveform of the magnetic flux density distribution represented by values of the waveform parameters which are in the appropriate ranges obtained in the above section and close to a sine wave are estimated.

In this study, three types of models were created, namely model 1 , Model 2 and model 3 , as models of the rotor 10 for use in simulations. For each model, the waveform was in the air gap 50 generated magnetic flux density distribution by performing a simulation by electromagnetic field analysis according to a finite element method (FEM) estimated.

In this study, the radius R of the rotor core was set to 83 mm in all models, and the number of poles was set to eight. The fat T was set as 3.0 mm for all permanent magnets and was assumed to have the same remanence. In all models became the centers c the circular arc shapes of the permanent magnets of the three layers set to the same position, and the distance R _θ was set as 85 mm. No flow barrier was provided in each model. Each of the permanent magnets was disposed in the associated slot at the outermost position in the longitudinal direction. The magnetization direction of each of the permanent magnets was set to coincide with the radial direction (radial orientation), and the focal point of the magnetization directions was set to coincide with the focal point of the shapes.

Conditions met in the simulations are summarized in the following Table 1.
Table 1 outer rotor diameter (mm) 166 outer stator diameter (mm) 264 Width of the air gap (mm) 0.8 Number of (division) slots 48 Number of poles 8th Lamination Thickness (mm) 50 permanent magnets Nd-Fe-B magnets Maximum current (A _rms ) 170 Maximum speed (rpm) 13500 nuclear material silicon steel

The 8A and 8B to 10A and 10B show arrangements in the model 1 to model 3 used permanent magnets and obtained by simulations magnetic flux density distributions.
The main configuration parameters in the model 1 to model 3 used permanent magnets are summarized in Table 2. Values of waveform parameters α . β . γ . A and B , which are read from the waveforms obtained by simulations, are also shown in Table 2.
Table 2 Model 1 Model 2 Model 3 θ1 (°) 8.7 4.8 8.7 θ2 (°) 14.5 16.5 14.5 θ3 (°) 18.8 20.1 18.8 θ _M1 (°) 45.0 50.0 30.0 θ _M2 (°) 42.5 50.0 40.0 θ _M3 (°) 38.75 55.0 50.0 R1 (mm) 16.0 10.6 16.0 R2 (mm) 24.3 27.2 24.3 R3 (mm) 30.45 32.3 30.45 α (°) 35 24 60 β (°) 60 72 60 γ (°) 80 87 78 A 0.72 0.66 1:00 B 12:40 12:59 0.87

In model 1 is how in 8B 10, the waveform of the magnetic flux density distribution obtained by simulation is such that the magnetic flux density varies little around the maximum and the minimum and varies relatively steeply around a midpoint between the maximum and minimum, and thus is close to a sine wave; and, as shown in Table 2, the values of the waveform parameters fall α . β . γ . A and B within the respective, in section ( 1 - 1 ), in which the THD can be made small. In particular, the values of α . β and γ approximately equal to the center values of the appropriate ranges.

Because, as mentioned above, R = 83 mm and R = 85 mm _θ is R0 = R (1 + cos _r) / 2cosθ _r equal to 86.4 mm. Thus, in model 1 the distance R _{θ of} the center c the circular arc shapes of the permanent magnets smaller than R0 , In model 1 meet, as shown in Table 2, the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets of the respective layers have the relation of the inequality (1) which should be satisfied when R _θ <R0; namely, θ _M3 <θ _M2 <θ _M1 .

On the other hand, in model 2 , as in 9B shown, the waveform of the magnetic flux density distribution around the maximum and the minimum around. In model 3 indicates the waveform of the magnetic flux density distribution as in 10B shown, flat area and steep areas. In this respect, the waveform of the magnetic flux density distribution is in model 2 and model 3 very different from a sine wave. In addition, the waveform parameters fall α . β . γ and B as shown in Table 2, in model 2 not in the respective ones in the above section ( 1 - 1 ) obtained appropriate range. In model 3 none of the waveform parameters falls α, β . γ . A and B in the appropriate area.

In model 2 obey the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets of the respective layers of the relationship θ _M1 = θ _M 2 <θ _M3 . In model 3 obey the opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnet of the relationship θ _M1 <θ _M2 <θ _M3 . The relation of inequality (1), which should be satisfied if Re <R0, is not satisfied in both cases.

As described above, an arrangement of the permanent magnets that gives a waveform of the magnetic flux density distribution in which harmonic components are reduced can be determined by making the waveform parameters α . β . γ . A and B within the respective, in section ( 1 - 1 ) by a simulation waveform of the magnetic flux density distribution, in which the values of the sets of configuration parameters of the permanent magnets are appropriately set, such as the opening angles θ _M1 . θ _M2 and θ _M3 , Such an arrangement of the permanent magnets satisfies the relationship between the opening angles θ _M1 . θ _M2 and θ _M3 given by the inequality (1) when R _θ <R0. Similarly, when R _θ ≥ R0, it was confirmed that the relationship between the opening angles θ _M1 . θ _M2 and θ _M3 given by the inequality (2) is satisfied by an arrangement of the permanent magnets with which the waveform parameters fall within the appropriate ranges.

In addition, iron losses that occur when the rotors 10 the models 1 - 3 be used in the engine, determined by simulations. 11 Figure 11 is a graph comparing the unloaded iron losses obtained when the respective rotors were operated at a speed of 13000 rpm. In 11 were the unloaded iron losses of the models 1 - 3 on the value of the model 1 normalized (its iron loss was assumed to be "1").

As in 11 shown is the iron loss of the model 1 smaller than the iron losses of model 2 and model 3 , The iron loss of model 1 is only about 70% of the iron loss of the model 2 that under the models 1 - 3 has the largest. This indicates that the iron loss of the motor can be reduced and the efficiency of the motor can be increased by selecting the values of the configuration parameters of the permanent magnets so as to give a waveform of the magnetic flux density distribution in which the contributions of the harmonic components are small ,

(1-3) Opening angle and center positions of the arc-shaped permanent magnets Next, a correlation will be made between the positions of the centers of the arc shapes of the permanent magnets of the respective layers and the opening angles θ _M1 . θ _M2 and θ _M3 the permanent magnets examined.

More specifically, a waveform of the magnetic flux density distribution in the air gap was simulated while the positions of the centers of the arc shapes of the permanent magnets were varied. The opening angle θ _M1 . θ _M2 and θ _M3 the permanent magnets of the respective layers have been set to give values of the waveform parameters which are listed in the 1 - 1 ) estimated appropriate areas. The positions of the centers of the circular arc shapes of the permanent magnets of the three layers were set as the same, and the distance from the center of rotation O of the rotor core to the center c The circular arc shapes of the permanent magnets was through R _θ represents.

As in section ( 1 - 2 ), the radius R of the rotor core became independent of the position of the center c the circular arc shapes of the permanent magnets set to 83 mm. The number of poles was set to eight. The fat T was set to 3.0 mm in all permanent magnets and was assumed to have the same remanence. The center angle θ1 . θ2 and θ3 the permanent magnets were set at 8.7 °, 14.5 ° and 18.8 °, and the radii R1 . R2 and R3 The circular arc shapes of the permanent magnets were on 16.0 mm, 24.3 mm and 30.45 mm respectively, regardless of the position of the center c the circular arc shapes of the permanent magnets.

The 12A to 12E show arrangements of permanent magnets in which the distance R _θ from the center of rotation O of the rotor core to the center c of the circular arc shapes of the permanent magnets was set to 85.0 mm, 87.5 mm, 90.0 mm, 92.5 mm and 95.0 mm, respectively, and for which it was confirmed that the waveform parameters fell within the appropriate ranges. Table 3 shows values of the opening angles θ _M1 . θ _M2 and θ _M3 the permanent magnets of each of the three layers for each of the above values of the distance R _θ ,
Table 3 R _θ 85.0 mm 87.5 mm 90.0 mm 92.5 mm 95.0 mm θ _M1 (°) 41.25 36.7 33.3 32.5 32.1 θ _M2 (°) 38.75 37.5 35.0 36.0 34.5 θ _M3 (°) 35.0 33.3 32.5 32.5 31.8 relationship θ _M3 <θ _M2 <θ _M1 θ _M3 ≤ θ _M1 <θ _M2

For all of the models were for which simulations carried out, applies R0 = R (1 + cos _r) / 2cosθ _r = 86.4 mm. In the model in which R _θ = 85.0 mm and a relation R _θ <R0 is satisfied, the opening angles satisfy θ _M1 . θ _M2 and θ _M3 The permanent magnets of the respective layers have a relation θ _M3 <θ _M 2 <θ _M1 . On the other hand, in the models in which R _θ = 87.5 to 95.0 mm and R _θ ≥ R0 is satisfied, the opening angles are satisfied θ _M1 . θ _M2 and θ _M3 the permanent magnets of the respective layers have a relation θ _M3 ≤ θ _M1 <θ _M2 .

oder $${\mathrm{\theta }}_{\text{M}3}\le {\mathrm{\theta }}_{\text{M}1}<{\mathrm{\theta }}_{\text{M}2}\left({\text{wenn R}}_{\mathrm{\theta }}\ge \text{R0}\right).$$

From the above description, it can be understood that a waveform of the magnetic flux density distribution in the air gap of the engine, at which the contributions of the harmonic components are reduced, can be obtained by taking a relationship between the opening angles θ _M1 . θ _M2 and θ _M3 the permanent magnets depending on the position of the center c the circular arc shapes of the permanent magnets is determined. It can be seen that the relationship between the opening angles θ _M1 . θ _M2 and θ _M3 the respective permanent magnets should read: $${\mathrm{\theta }}_{\text{<figure-callout id="3" label="M" filenames="DE102019110013A1\_0032.png,DE102019110013A1\_0038.png" state="{{state}}">M</figure-callout>}3}<{\mathrm{\theta }}_{\text{<figure-callout id="2" label="M" filenames="DE102019110013A1\_0030.png,DE102019110013A1\_0038.png" state="{{state}}">M</figure-callout>}2}<{\mathrm{\theta }}_{\text{M}1}\left({\text{if R}}_{\mathrm{\theta }}<\text{R0}\right)$$

or $${\mathrm{\theta }}_{\text{M}3}\le {\mathrm{\theta }}_{\text{M}1}<{\mathrm{\theta }}_{\text{M}2}\left({\text{if R}}_{\mathrm{\theta }}\ge \text{R0}\right),$$

(2) Comparison with Other Types of Arrangement of Permanent Magnets As described above, in the rotor according to the embodiment of the present invention, reduction of the harmonic components of the waveform of the magnetic flux density distribution generated in the air gap is achieved by appropriately arranging the plurality of arc-shaped permanent magnets, and the sets of configuration parameters of the permanent magnet are set appropriately. On the other hand, various types of structures of a rotor core for reducing harmonic components of the waveform of the magnetic flux density distribution have heretofore been proposed. The effects of reducing the harmonic components of these types of structures of a rotor core are compared below.

1. (a) Einzellage, V-förmige Anordnung #1: Ein dicker Flachplatten-Permanentmagnet ist in einer Lage in V Form angeordnet. Der Rotorkern weist Flusssperren auf. Die Außenumfangsoberfläche des Rotorkerns weist Dellen auf.
2. (b) Einzellage, V-förmige Anordnung #2: Dieses Modell weicht von Modell (a) insofern ab, als die Außenumfangsoberfläche des Rotorkerns keinerlei Dellen aufweist.
3. (c) Einzellage, V-förmige Anordnung #3: Ein dünner Flachplatten-Permanentmagnet ist in einer Lage in V-Form angeordnet. Der Rotorkern weist keinerlei Flusssperren auf und die Außenumfangsoberfläche des Rotorkerns weist keinerlei Dellen auf.
4. (d) Doppellage, V-förmige Anordnung: Ein V-förmiger Flachplatten-Permanentmagnet ist der Außenumfangsseite des Permanentmagneten von Modell (c) hinzugefügt.
5. (e) V-Anordnung: Ein Permanentmagnet ist zwischen den äußeren Enden, in ihrer longitudinalen Richtung, der beiden Teil-Permanentmagnete von Modell (c) eingefügt, die in V-Form angeordnet sind. Die drei Permanentmagnete sind im Dreieck angeordnet.
6. (f) Dreifachlage, Kreisbogen-förmige Anordnung: Dies ist die in der Ausführungsform der vorliegenden Erfindung eingesetzte Anordnung. Alle Permanentmagnete erzeugen dieselbe magnetische Flussdichte.

Six rotor core models, as in ( a ) to ( f ) from 13 are designed as follows:

1. (a) Single Layer, V-Shape # 1: A thick flat-plate permanent magnet is placed in a V-shape layer. The rotor core has flow barriers. The outer peripheral surface of the rotor core has dents.
2. (b) Single Layer, V-Shape # 2: This model differs from Model (a) in that the outer circumferential surface of the rotor core does not have any dents.
3. (c) Single Layer, V-Shape # 3: A thin flat-plate permanent magnet is disposed in a V-shape layer. The rotor core has no flux barriers and the outer peripheral surface of the rotor core has no dents.
4. (d) Double Layer, V-shaped Arrangement: A V-shaped flat-plate permanent magnet is the outer peripheral side of the permanent magnet of Model ( c ) added.
5. (e) V-arrangement: a permanent magnet is between the outer ends, in their longitudinal direction, of the two partial permanent magnets of model ( c ), which are arranged in V-shape. The three permanent magnets are arranged in a triangle.
6. (f) Triple sheet, circular arc-shaped arrangement: This is the arrangement used in the embodiment of the present invention. All permanent magnets produce the same magnetic flux density.

The volumes of the sets of permanent magnets of the respective models are set so that the number of flux connections of the permanent magnets in the respective models is approximately the same.

In each model, a waveform of the magnetic flux density distribution in the air gap was estimated by performing a simulation using a finite element method (described above). The conditions used in the simulations are summarized in the following Table 4. The permanent magnets had magnetization directions of radial orientation, and the focal points of the magnetization directions of each of the permanent magnets coincided with the focal point of its shape.
Table 4 outer rotor diameter (mm) 160 outer stator diameter (mm) 264 Width of the air gap (mm) 0.8 Number of (division) slots 48 Number of poles 8th Lamination Thickness (mm) 50 permanent magnets Nd-Fe-B magnets Maximum current (A _rms ) 170 Maximum speed (rpm) 13500 nuclear material silicon steel

(a) to (f) in 14 show simulation results. In the simulations, a closed-slot type stator was assumed in which the teeth are connected together to form a one-piece body. As in ( a ) to ( f ) in 14 As shown, the models generate different waveforms. It is clear that the waveforms of at least ( b ) Single layer, V-shaped arrangement # 2, ( c ) Single layer, V-shaped arrangement # 3 and ( e ) V-arrangement deviate strongly from a sine wave.

(a) to (f) in 15 show results of analysis, the fractions of a fundamental wave and harmonic waves of the respective orders by Fourier transforming each of (a) to (f) in FIG 14 calculated waveforms calculated. In ( a ) to ( f) in 15 are ratios of the magnetic flux densities Bn of respective order n waves in terms of magnetic flux density B1 of a fundamental wave (n = 1) normalized values. It can be seen that the proportions of the magnetic flux densities Bn of harmonic components in ( b ) Single layer, V-shaped arrangement # 2, ( c ) Single layer, V-shaped arrangement # 3, and (e) V-arrangement are significantly larger than in the other arrangements. It can also be seen that the proportions of harmonic waves of relatively low order, namely harmonic waves of the third and fifth order, in (a) single layer, V-shaped device # 1 and (d) double layer, V-shaped device are larger than in (f ) three-layer, arcuate arrangement.

16 is a graph corresponding to that of (a) to (f) in 15 shown results of the total harmonic distortion. Each value of the total harmonic distortion was calculated as the ratio of the sum of all harmonic waves (n ≥ 2) to the sum thereof and the proportion of the harmonic waves Fundamental wave (n = 1) calculated. One recognizes 16 that the total harmonic component in ( f ) three-layered, arcuate arrangement is smallest (about 20%) among the total harmonic components of all modes. The entire harmonic component is at ( a ) Single layer, V-shaped arrangement # 1 on the second smallest, and the entire harmonic component is at ( f ) three-layered, arcuate arrangement at least about 14% smaller than in the arrangement ( a ).

The proportion of harmonic waves in the waveform of the magnetic flux density distribution in the air gap is closely related to the iron loss in the rotor core. (a) to (f) in 17 are graphs, each of which shows values for the unloaded iron loss estimated by a simulation in which the contributions of the fundamental wave and the contributions of the harmonic waves are shown separately. The contributions of the fundamental wave (first order) are given as a numerical value in each figure.

One recognizes ( a ) to ( f ) in 17 that the iron loss by the fundamental wave at ( f ) three-layered, arcuate arrangement is the second largest, next to at ( c ) Single layer, V-shaped arrangement # 3. However, the iron losses are due to harmonic waves at ( f ) Three-layer, arcuate arrangement significantly smaller than the other models.

18 is a graph for comparing the unloaded iron losses of the respective models, each containing unencumbered iron losses of the fundamental wave and all harmonic waves. The sequence of increase of the unloaded iron losses of the respective models in 18 coincides with the sequence of increasing the values of the total harmonic distortion of the respective model 16 , which means that the unloaded iron losses are highly correlated with the proportions of all harmonic waves of the magnetic flux density distribution waveform.

The unloaded iron losses at ( f ) Three-ply arc-shaped arrangement are also the smallest, as is their value of total harmonic distortion. The unloaded iron loss at ( f ) three-layered, arcuate arrangement is about 9% smaller than the (second smallest) unstressed iron loss at ( a ) Single layer, V-shaped arrangement # 1.

It is concluded from the above discussion that harmonic components of the waveform of a magnetic flux density distribution formed in the air gap can be reduced by using a (FIG. f ) three-layer, arcuate arrangement, namely by arranging circular arc-shaped permanent magnet in three layers. The reduction of harmonic components by using permanent magnets having these shapes and arrangement suppresses phenomena caused by harmonic waves such as iron loss and torque ripple.

Although the formation of dents in the outer peripheral area of the rotor core as in ( a ) Single layer, V-shaped arrangement # 1 and the application of ( e ) Are effective in reducing harmonic waves, they tend to result in a reduction in the output torque of the motor (rotor). More specifically, the formation of dents in the outer peripheral area of the rotor tends to reduce the reluctance torque by increasing the equivalent air gap width. At ( e V-arrangement, local magnetic saturation occurs in the rotor and tends to reduce the reluctance torque. In contrast, in the case that harmonic components can be generated by using ( f ) three-layered arcuate arrangement, the harmonic components of the waveform of the magnetic flux density distribution are reduced while the reluctance torque is made large.

Although the embodiment of the present invention has been described in detail, the present invention is not limited to the embodiment described above, and various modifications are possible without departing from the spirit of the present invention.

In the permanent magnet rotor 10 according to the embodiment of the present invention, which the rotor core 11 and several permanent magnets 16 . 17 and 18 includes that in the rotor core 11 are embedded and each forming a magnetic pole, have the permanent magnets 16 . 17 and 18 each has an arc shape such that it faces the inner peripheral side of the rotor core 11 convex and in two or more layers from the outer peripheral side to the inner peripheral side of the rotor core 11 are arranged, and the opening angle θ _M1 . θ _M2 and θ _M3 the arc shape of the permanent magnets 16 . 17 and 18 and / or their remanence Br1 . Br2 and Br3 satisfy a prescribed relationship, reducing the effect of reducing harmonic components of the waveform in the air gap 50 generated magnetic flux density distribution is obtained.
However, the present invention is not limited to the case that the opening angle θ _M1 . θ _M2 and θ _M3 the arc shape of the permanent magnets 16 . 17 and 18 and / or their remanence Br1 . Br2 and Br3 the fulfill prescribed relationship. In a permanent magnet rotor, which is the rotor core 11 and several permanent magnets 16 . 17 and 18 that involves in the rotor core 11 are embedded, and form each magnetic pole, each having such an arc shape that it to the inner peripheral side of the rotor core 11 is convex, and in two or more layers (especially in three layers) from the outer peripheral side to the inner peripheral side of the rotor core 11 are arranged, have the permanent magnets 16 . 17 and 18 Magnetization directions that are radially aligned, and also fall the focal points of the magnetization directions of the permanent magnets 16 . 17 and 18 with the focal points of their forms together. This permanent magnet rotor also provides the effect of reducing the harmonic components of the waveform of the magnetic flux density distribution generated in the air gap.

The present application is based on Japanese Patent Application No. 2018-079151 , filed on Apr. 17, 2018, the contents of which are hereby incorporated by reference.

LIST OF REFERENCE NUMBERS

1:

Motor (electric rotary machine)

10:

Rotor (permanent magnet rotor)

11:

rotor core

11a:

Outer peripheral surface of the rotor core

11b:

dent

12:

Hollow area

13:

Slit of the first layer

14:

Slot of the second layer

15:

Slit of the third layer

16:

First sheet permanent magnet

17:

Second sheet permanent magnet

18:

Third position permanent magnet

20:

check valve

21:

bridge

22:

room

30:

stator

50:

air gap

c:

Center (focal point) of each permanent magnet

c1:

Center (focal point) of the first-position permanent magnet

c2:

Center (focal point) of the second position permanent magnet

c3:

Center (focal point) of the third-position permanent magnet

d ':

d axis of the rotor

q ':

Axis (q'-axis) which is offset by 90 ° from the d-axis of the rotor at an electrical angle

L1, L2:

Interlayer distance

θ _M1 :

First sheet opening angle

θ _M2 :

Second sheet angle

θ _M3 :

Third-capable opening angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2002078259 A [0004]
• JP 2018079151 [0137]

Claims (9)

Permanent magnet rotor comprising: a rotor core; and a plurality of permanent magnets embedded in the rotor core and each constituting a magnetic pole, the plurality of permanent magnets each having an arcuate shape to be convex to an inner peripheral side of the rotor core and stacked in three or more layers from an outer peripheral side to the inner one And the opening angles θ _M1 , θ _M2, and θ _{M3 of} the arc shapes of the permanent magnets disposed in the first, second, and third positions, respectively, from the outer circumferential side of the rotor core satisfy the following relationship: $${\mathrm{\theta }}_{\text{M}3}<{\mathrm{\theta }}_{\text{M}2}<{\mathrm{\theta }}_{\text{M}1}{\text{if R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}.$$

or $${\mathrm{\theta }}_{\text{M}3}\le {\mathrm{\theta }}_{\text{M}1}<{\mathrm{\theta }}_{\text{M}2}{\text{if R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}$$

wherein R _{θ is} a distance from a rotation center of the rotor core to an average position of the focal points of the arc shapes of the permanent magnets disposed in the first, second and third layers, R is a distance from the center of rotation of the rotor core to the outer periphery of the rotor core, n is the number of magnetic poles is, and θ _r = 180 ° / n. Permanent magnet rotor according to Claim 1 wherein the remanences Br1, Br2 and Br3 of the permanent magnets disposed in the first, second and third positions, respectively, from the outer circumferential side of the rotor core satisfy the following relationship: $$\text{br}3<\text{br}2<\text{br}1{\text{if R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}.$$

or $$\text{br}3\le \text{br}1<\text{br}2{\text{if R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}},$$

Permanent magnet rotor with: a rotor core; and a plurality of permanent magnets embedded in the rotor core and each constituting a magnetic pole, the plurality of permanent magnets each having an arcuate shape to be convex to an inner peripheral side of the rotor core and stacked in three or more layers from an outer peripheral side to the inner one Are arranged on the circumferential side of the rotor core, and remanences Br1, Br2 and Br3 of the arranged in the first, second and third layer from the outer peripheral side of the rotor core permanent magnets satisfy the following relationship: $$\text{br}3<\text{br}2<\text{br}1{\text{if R}}_{\mathrm{\theta }}<\text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}.$$

or $$\text{br}3\le \text{br}1<\text{br}2{\text{if R}}_{\mathrm{\theta }}\ge \text{R}\left(1+\text{cos}{\mathrm{\theta }}_{\text{r}}\right)\text{/}2\text{cos}{\mathrm{\theta }}_{\text{r}}$$

wherein R _{θ is} a distance from a rotation center of the rotor core to an average position of the focal points of the arc shapes of the permanent magnets disposed in the first, second and third layers, R is a distance from the center of rotation of the rotor core to the outer periphery of the rotor core, n is the number of magnetic poles is, and θ _r = 180 ° / n. Permanent magnet rotor comprising: a rotor core; and a plurality of permanent magnets embedded in the rotor core and each constituting a magnetic pole, the plurality of permanent magnets each having an arcuate shape to be convex to an inner peripheral side of the rotor core, and two layers from an outer peripheral side to the inner peripheral side of the rotor core and opening angles θ _M1 and θ _{M2 of} the arc shapes of the permanent magnets disposed in the first and second layers from the outer circumferential side of the rotor core, respectively, satisfy the following relationship: $${\mathrm{\theta }}_{\text{M}2}<{\mathrm{\theta }}_{\text{M}1},$$

Permanent magnet rotor according to Claim 4 wherein remanences Br1 and Br2 of the permanent magnets disposed in the first and second positions from the outer circumferential side of the rotor core, respectively, satisfy the following relationship: $$\text{br}2<\text{br}1.$$

Permanent magnet rotor according to one of Claims 1 to 5 wherein the foci of the arc shapes of the plurality of permanent magnets are arranged separately in the same order from the outer peripheral side to the inner peripheral side of the rotor core as the plurality of permanent magnets. Permanent magnet rotor according to one of Claims 1 to 6 wherein the plurality of permanent magnets comprise metal magnets. Electric rotary machine comprising: the permanent magnet rotor according to any one of Claims 1 to 7 ; and a stator disposed so as to leave an air gap between the permanent magnet rotor and the stator. Electric rotary machine according to Claim 8 which has an overall harmonic distortion of the magnetic flux density distribution waveform formed by the plurality of permanent magnets in the air gap of less than or equal to 23%.

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