JPH09261931A - Rotating-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating-electric machine not only driven with 3 phases but also with other number of phases, with the expanded degree of freedom to select the number of pole in the yoke for one driven phase, in which the torque ripple characteristics are improved and the cogging is suppressed. SOLUTION: In the number of pole of a magnet assembly 30 is denoted by (n) (an integer which expresses the numbers of pairs of S-poles and N-poles), the number of driven phase in the windings of an armature 10 is denoted by (k) (an integer) and the number of coil pole for one driven phase of the armature 10 is denoted by (m) (an integer), both the following conditions are satisfied simultaneously: (1) (n) and (k) have no common measure, (2) the value of (n)/ (k)×(m)} is 1/2 or approximately the multiple of 1/2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electric motor.
Alternatively, it relates to improvement of a rotary electric machine used as a generator.

[0002]

2. Description of the Related Art As a rotary electric machine, for example, an electric motor includes a coiled armature and a magnet assembly having a plurality of magnets. In such a synchronous rotary electric machine, for example, when the magnet assembly side is the rotor and the armature is the stator, the drive voltage supply speed to the excitation coil of the armature is the same as that of the rotor magnet assembly. It is designed to synchronize with the rotation speed. In such an electric motor (or generator), whether the number of poles of the magnet of the magnet assembly that is the rotor (the number of S poles and the number of N poles counted) is the same as the number of poles of the coil yoke of the armature, Alternatively, when there is a multiple relationship, the drive torque or the induced voltage is maximized, which is advantageous in terms of motor performance. On the other hand, in a motor with such an ideal structure, when the magnetizing method of each magnet of the rotor and the shape of the yoke do not have the ideal characteristic values as designed as a result of manufacturing, those magnets are used. Due to the poor magnetization or the poor shape of the yoke, the ripple of the driving torque is maximized, which makes the motor rather difficult to use.

[0003]

Therefore, in order to avoid such a problem, the number of poles of the magnet and the number of poles of the yoke are not the same or have a multiple relationship, but the number of poles of the yoke and the poles of the magnet are not. Proposals to actively change the number,
For example, it is disclosed in Japanese Patent Laid-Open No. 3-198645. However, the number of drive phases of such a motor is limited to only three, and a synchronous motor which originally intends to perform multi-phase drive such as 2, 3, 4, ... It has a drawback that it cannot be generally applied as a synchronous motor. Moreover, in actual production, the number of poles of the coil of the yoke becomes larger than the number of poles of the magnet, which makes winding difficult and restricts the shape of the yoke. However, there is a problem in that there is a contradiction in which the so-called cogging (as a jerky motion that is not smooth) and the torque ripple fluctuate. Therefore, the present invention has been made to solve the above problems, and the number of drive phases is not limited to three, and the degree of freedom in selecting the number of poles of a magnet or the number of poles of a yoke corresponding to the number of drive phases is expanded. Then, it aims at providing the rotary electric machine which can improve the characteristic of a torque ripple and can reduce cogging.

[0004]

According to the present invention, there is provided a synchronous rotary electric machine including an armature and a magnet assembly, wherein the number of magnetic poles of the magnet assembly is n (pair of S pole and N pole). And an integer for expressing the number of
The number of drive phases given to the winding of the armature is k (integer), and the number of coil poles per phase of the number of drive phases k of the armature is m.
As (integer), the condition (1) the number of magnetic poles n and the number of drive phases k are
By the rotary electric machines that are “prime” to each other and satisfy the condition (2) the number of magnetic poles n / (the number of drive phases k × the number of coil poles m) is ½ or almost a multiple of ½, To be achieved.

In the present invention, the fact that the number of magnetic poles n and the number of drive phases k are "prime" mutually means that the composite vector of the phase voltage of one coil and the composite vector of the phase voltage of another coil do not overlap and are evenly arranged. Therefore, the drive phases that have been made multi-phase do not overlap. This can reduce the torque ripple. Moreover, the number of magnetic poles n / (the number of driving phases k × the number of coil poles m)
By simultaneously satisfying that the value of is 1/2 or a multiple of 1/2, the following can be achieved. The phase voltages in the armature can be grouped and when each phase voltage is grouped, the ripple can be dispersed during rotation.

In the present invention, the above object is as follows: when the order of the number m of coil poles per phase of the number k of driving phases is i,
[Number of magnetic poles n / (number of drive phases k × number of coil poles m)] × (i-
The winding direction of the pole coil whose value of 1) is close to odd multiples of 1/2 (integer multiple) and the coil of poles close to even multiples of 1/2 (zero and integer multiples) is opposite. Achieved by some rotating electrical machines. In the present invention, preferably [the number of magnetic poles n /
(The number of driving phases k × the number of coil poles m)] × (i-1) is 1
If the winding direction of the pole coil that is closer to an odd multiple of / 2 and that of the pole coil that is closer to an even multiple of 1/2 are opposite, the following can be done. By reversing the direction, a group of vector of a certain phase voltage and a group of vector of another phase voltage can be combined, and a combined vector of phase voltage with a larger absolute value can be generated, whereby a high voltage can be obtained. A small generator can be realized. Alternatively, an electric motor that can obtain a phase current having a larger absolute value can be realized. Both can be obtained by changing the connection form of the coil.

In the present invention, preferably, the coils of the poles which are close to odd multiples of 1/2 and the coils of the poles which are close to even multiples of 1/2 can be connected in series or in parallel. Such a rotary electric machine can be used as an electric motor or a generator.

[0008]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limitations are given, the scope of the present invention is not limited to these modes unless otherwise specified to limit the present invention. FIG. 1 shows a generator 100 as an example of the rotating electric machine of the present invention. The generator 100 is an armature 1
0, magnet assembly 30, and magnet case 5
It has 0. In this generator 100, the armature 10 is a stator and the magnet assembly 30 is a rotor, so this generator 100 is a so-called outer rotor type motor. The magnet assembly 30 is housed in the magnet case 50. The armature 10 is located in the center of the hollow portion of the magnet assembly 30.

The armature 10 has eight yokes 31 to 38. These yokes 31-38 are slot 4
1 to 48, they are arranged so as to protrude toward the magnet assembly 30 side along the radial direction at equal yoke pitches θ. These yokes 31 to 38 have a coil C1.
1 to C42 are wound. The yoke 31 of the armature 10
Is formed by stacking a plurality of flat materials such as ferromagnetic materials, for example, silicon steel plates. Of the eight yokes 31 to 38, the yokes 31 and 32 correspond to the drive phase k = 1, the yokes 33 and 34 correspond to the drive phase k = 2, and the yokes 35 and 36 correspond to the drive phase k = 3. Correspondingly, and the yokes 37, 38 correspond to the drive phase k = 4.
In other words, this motor has a drive phase number k =
It is 4 phases of 4. And in each drive phase k = 1 to k = 4,
As shown in FIG. 2, the number of coil poles is m = 2.
That is, in the drive phase k = 1, the number of coil poles is equal to the coil C1.
It has two coils like 1 and C12. The same applies to the other drive phases k2, k3, k4.

On the other hand, in the magnet assembly 30, three sets of N-pole and S-pole magnets 51 and 52 are arranged along the circumferential direction. Magnet assembly 3 in this case
The number of poles of the rotor magnet of 0 is n = 3 as shown in FIG. That is, in the present invention, the pair of the N pole 51 and the S pole 52 is defined as n = 1, so that a total of six N poles 51 and S poles 52 are provided.
Has the number of poles of the rotor magnet n = 3. Each N pole 5
The 1 and S poles 52 can be made of, for example, ceramic ferrite or rare earth cobalt. In FIG. 3, the magnet assembly 30 includes the armature 1 via the support 49.
It is structured so that it can rotate with respect to zero. As the support 49, a conventionally used outer rotor type support can be used.

The characteristics of the generator 100 shown in FIG. 1 will be described with reference to FIG. As described above, the number of poles of the magnet assembly 30 (rotor magnet) is n = 3 as described above. Number of drive phases k of armature 10
Is 4. That is, the number of drive phases is four. In this case, the number of coil poles of each drive phase k1 to k4 is m = 2. The number of poles n, the number of drive phases k, and the number of coil poles m are
Each is an integer. And the magnet assembly 3
The number n of poles of 0 and the number k of drive phases are “prime” relative to each other, which means that they are mathematically relatively prime.

Moreover, in the electric motor 100 of FIG. 1, the value of [the number of magnetic poles n / (the number of drive phases k × the number of coil poles m)] is 1/2.
Alternatively, it is necessary to simultaneously satisfy that it is a multiple of 1/2. In the generator 100 of FIG. 1, since the number of poles n is 3, the number of drive phases k is 4, and the number of coil poles m is 2, as shown in FIG. 2, the number of magnetic poles n / (the number of drive phases) The value of k × the number of coil poles m) is 3/8, but the value of 3/8 is
It is a value close to 1/2.

As shown in FIG. 4, eight coils C11, C12, C21, C22, C31, C3 of the armature 10 are provided.
2, C41 and C42 are connected. That is, drive phase k1
The coils C11 and C12 are reverse winding connections and series connections. Similarly, the coils C21 and C22 of the drive phase k2
Are reverse winding connections and series connections. The coils C31 and C32 of the drive phase k3 are reverse winding connection and series connection.
The coils C41 and C42 of the drive phase k4 are reverse winding connection and series connection.

The armature 10 of FIG. 4 has drive phases k1 to k4.
In the above, the coils are connected in series, but the coils are reversely connected in each drive phase for the following reason. Hereinafter, the reason for the reverse winding connection will be described. As shown in FIG. 1, the magnet assembly 3
Assuming that the period of the N pole 51 and the S pole 52 of 0 is λ, the period can be represented by λ = 2π / n (120 °). And one yoke pitch is θ (45 °). As an example, let us focus on the drive phase k1 of the armature 10 and consider the generated voltage. The phase voltage V11 generated by the rotation of the magnet assembly (rotor magnet) 30 in the coil C11 of the yoke 31 having the number m of coil poles in the order i = 1 can be expressed by Equation 1.

[Equation 1] As a result, a phase voltage V12 having a phase (electrical angle) shift of (θ × 2π / λ) is generated in the coil C12 of the yoke 32 having the order i = 2 by the following equation.

[Equation 2] Then, generally, the phase voltage V1i generated in the coil of the yoke corresponding to the order i = i is as follows.

(Equation 3)

The phase voltage V11 and the phase voltage V thus obtained
When 12 is represented by a vector, it can be represented by vector coordinates as shown in FIG. Assuming that the phase voltage V11 is along the X axis, the phase voltage V12 is θ × 2π / λ = from the phase voltage V11.
It can be displayed with a phase shift of (2π × n) / (k × m) = 135 °. And the coil C2 of the yoke 33 in the order i = 3
The phase voltage V13 generated at 1 and the phase voltage V1i generated at the yoke of the order i = i can be displayed as shown in FIG. These phase voltages V11 and V13 are oriented in a direction about 180 ° apart from V12 and V1i.
It shows with. In this embodiment, the number of yokes (the number of coils) in FIG. 1 is eight, so the phase voltage V1i is V18.
It is.

The value of [the number of magnetic poles n / (the number of drive phases k × the number of coil poles m)] is 1/2 or a multiple of 1/2, and in particular, [the number of magnetic poles n / (the number of drive phases k ×) Number of coil poles m)] ×
Focusing on the value of (i-1), as shown in FIG.
1 and V13 face away from each other by about 180 ° with respect to the other phase voltages V12 and V1i, and the phase voltage V11
And group G1 of V13 and group G2 of phase voltages V12 and V1i. For example, if all the coil poles in the same phase such as the drive phase k1 in FIG. 1 are connected in series as in FIG. 4, a combined vector V1 of one phase voltage is obtained. The composite vector V1 of this phase voltage can be expressed as follows.

(Equation 4)

However, the above-described phase voltage composite vector V
1, the phase voltages V12 and V1i are in the direction in which the phase voltages V11 and V13 on the opposite side are weakened in vector as shown in FIG. Therefore, when the phase voltage V11 is used as the reference, the phase voltage composite vector V1 is increased as follows.

(Equation 5) The composite vector V1 of the phase voltages thus strengthened is shown in FIG.
It can be illustrated as a vector as shown in (A) and FIG. 7 (B). That is, by creating the phase voltage V12R of the vector in the opposite direction of the phase voltage V12 and the phase voltage V1iR of the vector in the opposite direction of the phase voltage V1i, the composite vector V1 of the phase voltage in one direction can be created. . As a result, the absolute value of the vector of the combined vector V1 of the phase voltages becomes maximum.

Thus, n / (k × m) is approximately 1/2
Alternatively, if it is approximately a multiple of 1/2, particularly when this value is preferably 1/4 <[n / (k × m)] <3/4, as shown in FIG. For example, it can be divided into two groups G1 and G2. FIG.
In the example, the group G1 has the phase voltages V11 and V13, and the group G2 has the phase voltages V12 and V1i. If the vector of each phase voltage belongs to the groups G1 and G2, the ripple during rotation can be reduced or dispersed. The vector of each phase voltage is group G1,
When G2 is properly grouped, as shown in FIG. 7, the combined vector V1 of phase voltages is easy to create or output.

As mentioned above, the generator 100 of FIG.
As is apparent from FIGS. 6 and 7, the group G is adjusted to match the phase voltages V11 and V13 of the group G1 of FIG.
If the two phase voltages V12 and V1i are inverted in vector,
The generated voltage corresponding to the combined vector V1 of the phase voltages in FIG. 7B can be obtained. That is, since the phase voltages V12 and V1i of the group G2 are coils corresponding to the poles of odd multiples of the phase of 180 °, by inverting the phase voltages V12 and V1i of the group G2 by 180 °, The combined vector V1 can be obtained easily and surely. An effective condition for performing such an inversion operation is (2π × n) / (k × m) is π (18
It must be close to an integral multiple of 0 °). That is, the following formula must be satisfied.

(Equation 6) Since each vector of the phase voltages V11 to V1i is inversely connected, the phase voltages are appropriately dispersed in the same direction, which contributes to the dispersion of the torque ripple of the combined vector V1 of the phase voltages. Moreover, it is possible to prevent waste of the generated voltage and easily create a combined phase voltage of the combined voltage V1 of the phase voltages.

Next, the phase voltage composite vectors V1 to V4
The relationship of (Vk) will be described. The combined vector V1 of phase voltages has a phase voltage V12R obtained by inverting the phase voltage V12 by 180 ° as shown in FIG. The combined vector V2 of the phase voltages has a phase voltage V22R obtained by inverting the phase voltage V22 by 180 ° as shown in FIG. The phase voltage V12R is oriented in the lower right direction in FIG. 8, and the phase voltage V22R is
In FIG. 8, it faces the lower left direction. The combined vector V1 of the phase voltages and the combined vector V2 of the phase voltages do not overlap in any case. Therefore, they must be evenly arranged in FIG. 8, but the condition of the uniform arrangement is that the magnet assembly 30 of FIG. It is a necessary and sufficient condition that the number of poles n and the number of drive phases k are mathematically “prime”.

FIG. 9 shows a composite vector V1, V2, V3 of the phase voltages of the generator 100 of FIG. 1 thus obtained.
An example of V4 is shown, and a composite vector V1 of each phase voltage is shown.
~ V4 are oriented in directions orthogonal to each other. In this case, the number of driving phases k is 4, and the magnet assembly 3
The number n of poles of 0 is 3. And the combined vector V of the phase voltage
1 to V4 are clockwise vectors.

As shown in FIGS. 11A and 11B, the phase vectors V11 and V12 are V as a composite vector of the phase voltages.
1 is formed, and the combined vector V1 is the phase voltage V11.
And the phase voltage V12R are added in vector. Similarly, the combined vector V2 of the phase voltages is a vector addition of the phase voltage V21 and the phase voltage V22R as shown in FIG. Combined vector of phase voltage V1, V2, V
3 and V4 are deviated by 90 ° in a four-phase motor having four drive phases. Since the number of poles n and the number of drive phases k of the magnet assembly 30 are “prime” to each other, as shown in FIG.
The combined vectors V1 to V4 of the phase voltages are orthogonal to each other. If n and k are not prime, any of the combined vectors V1 to V4 of the phase voltages will overlap, so there is no point in making multiple phases. FIG. 10 shows another example, and shows combined vectors V1 to V3 of phase voltages. In this case, the number of drive phases is k = 3, and the order of vectors varies depending on the number n of poles of the rotor magnet assembly 30. When the number of drive phases k and the number of poles n are not "prime", the vectors obviously overlap during one rotation of the rotor, and there is no point in making the number of drive phases multiphase. Moreover, the torque ripple naturally increases.

By the way, in the embodiment described above, FIG.
In the description, the generator 100 as shown in FIG.
However, the present invention is not limited to this, and various other modes can be considered. FIG. 13 shows an example of an electric motor, which has drive phases k1 to k4, and in each drive phase, coils are connected in parallel and in reverse winding. The coils C11 and C12 in the drive phase k1 are in parallel connection and reverse winding connection. Similarly, the coils C21 and C22 of the drive phase k2 are in parallel connection and reverse winding connection. Coils C31 and C3 of drive phase k3
2 is parallel connection and reverse winding connection. The coils C41 and C42 of the drive phase k4 are in parallel connection and in reverse winding connection.

By the way, when considering a DC generator as shown in FIG. 1, it is necessary to use a rectifier circuit. As this rectifier circuit, a rectifier circuit using a diode D and a resistor R as shown in FIG. 14 can be used. In FIG. 14, it is easy to understand if the temporary grounding is considered with respect to the midpoint. The output voltage in this case is the output VA at point A as shown in FIG.
And the output VB at point B appears, but in one cycle,
The voltage VA-VB changes from the state of (A) of FIG. 15 to the state of (B), and the ripple in one rotation can be represented by 2 × the number of driving phases k. That is, the larger the number of drive phases, the more the voltage ripple of the voltages VA-VB is improved.

As described above, according to the present invention, the number of magnetic poles n is not improved but the improvement of the torque ripple at the limited ratio (for example, n-1 / n) of the number of poles of the rotor magnet and the number of poles of the coil yoke as in the prior art. And the number of drive phases k are mutually prime, and the number of magnetic poles n of the magnet assembly, the number k of drive phases of the armature, and the number m of coil poles per phase of the number of drive phases of the armature are appropriately selected and combined. , [Number of magnetic poles n / (Number of drive phases k
By simultaneously satisfying that the value of (× coil pole number m)] is 1/2 or a multiple of 1/2, it is possible to freely design, and especially in the case of a generator, its effect is obtained. Remarkable. In the case of a generator, the rectifier circuit is often used as described above, and in that case, the number of phases can be set quite freely.
On the other hand, most of the power generation is currently three-phase, and the number of phases is limited, except when passing through an inverter. Further, the number of poles of the coil yoke, that is, the number m of coil poles per phase of the number k of drive phases of the armature can be reduced, and various problems associated with multipole winding can be reduced. The effect of reducing both the torque ripple (the detent torque and the torque during load operation) can be expected, as in the conventional rotating electric machines. This detent torque represents the maximum torque required to rotate the rotor in the state where no current flows in the coil, and is generated when the balance of the magnetic attraction force between the magnet and the yoke material changes according to the rotation angle. That is.

[0026]

As described above, according to the present invention,
The number of drive phases is not limited to three, and the degree of freedom in selecting the number of poles of the magnet or the number of poles of the yoke corresponding to the number of drive phases can be expanded to improve the characteristics of the torque ripple and reduce cogging. .

[Brief description of drawings]

FIG. 1 is a diagram showing a preferred embodiment of a generator as a rotary electric machine of the present invention.

FIG. 2 is a diagram showing an example of characteristics of the rotary electric machine shown in FIG.

FIG. 3 is a diagram showing each element of the rotary electric machine of FIG. 1.

FIG. 4 is a diagram showing an example of coil connection in each drive phase of the rotary electric machine of FIG. 1.

5 is a vector diagram showing an example of two phase voltages in the coil connection example of FIG.

6 is a diagram showing a state in which the phase voltage of FIG. 5 is divided into two groups.

7 is a diagram showing an example of outputting a combined vector of one phase voltage from the phase voltages of the two groups in FIG.

FIG. 8 is a diagram showing an example of forming a combined vector of two phase voltages.

FIG. 9 is a diagram showing a combined vector of four phase voltages.

FIG. 10 is a diagram showing a combined vector of three phase voltages.

FIG. 11 is a diagram showing a composite vector of one phase voltage from two phase voltages.

FIG. 12 is a diagram for creating a combined vector of one phase voltage from another two phase voltages.

FIG. 13 is a diagram showing an example of an electric motor (motor) in which coils of each drive phase are connected in series and connected in reverse winding.

FIG. 14 is a diagram showing an example of a rectifier circuit when using a DC generator.

15 is a diagram showing an example of an output voltage rectified by the rectifier circuit of FIG.

[Explanation of symbols]

10 ... Armature (stator), 30 ... Magnet assembly (rotor), 31, 32, 33, 34, 3
5,36,37,38 ... Armature yoke, 100
..Generators (rotary electric machines), C11, C12, C2
1, C22, C31, C32, C41, C42 ... Coil, k ... Number of drive phases, m ... Number of coil poles, n ...
・ Number of poles of magnet assembly (rotor magnet)

Claims (4)

[Claims] 1. A synchronous rotary electric machine comprising an armature and a magnet assembly, wherein the number of magnetic poles of the magnet assembly is n (an integer for representing the number of pairs of S poles and N poles), and winding of the armature. The number of drive phases to be given to k is an integer, and the number of coil poles per phase of the number of drive phases k of the armature is m (an integer). Condition (1) The number of magnetic poles n and the number of drive phases k are And the condition (2) the number of magnetic poles n / (the number of drive phases k × the number of coil poles m) is 1/2 or almost a multiple of 1/2 at the same time. Electric machine. 2. When the order of the number m of coil poles per phase of the number k of drive phases is i, [the number of magnetic poles n / (the number of drive phases k × the number of coil poles m)] × (i−
The winding direction of the pole coil whose value of 1) is close to odd multiples of 1/2 (integer multiple) and the coil of poles close to even multiples of 1/2 (zero and integer multiples) is opposite. The rotary electric machine according to claim 1. 3. A pole coil that is close to an odd multiple of 1/2 (an integer multiple) and a pole coil that is close to an even multiple of 1/2 (zero and integer multiples) are connected in series or in parallel. The rotary electric machine according to claim 2, wherein 4. The rotary electric machine according to claim 1, which is an electric motor or a generator.