DE19934775A1 - Electrically commutated electric motor, has rotor whose permanent magnet(s) form single magnet or it is formed of individual segments; north and south poles butt against each other - Google Patents

Abstract

The motor has n legs, where one leg consists of a stator with an iron short circuit ring (1) and a concentric coil (6), a rotor with an iron short circuit ring (7) and at least one permanent magnet. The rotor's permanent magnet(s) form only a single magnetic ring (5) or it is formed of individual segments. North and south poles of the permanent magnet(s) butt against each other and there are flux control areas in the stator that combine the magnetic fluxes of the north and south poles.

Description

The invention relates to the development of an engine principle for electronic commutated motors. A detailed description of the state of the art with regard to electronically commutated motors with higher power Hendershot literature reference "Design of brushless permanent magnet motors" given. After that, the electronically commutated motor consists of the following characteristic components:

1. Fixed stator

The stator consists of a sheet metal designed for eddy current reduction Iron circle and a winding usually made up of three phases. The sheet metal cut of the iron circle is divided into the characteristic parts tooth, hammer and Divided iron inference. In the tooth, hammer and iron yoke the winding is inserted in the enclosed area. The areas in which the Winding can be inserted, are called "slot". The iron circle can for different slot configurations can be designed.

2. Rotor

The rotor consists of an iron yoke and the flux-generating one Permanent magnets. The permanent magnet is radial or diametric  arranged pole pairs (P) magnetized. The number of poles (P2) corresponds to the number the polar areas magnetized in alternating polarity. The rotor can be used as an or external rotor motor. With the external rotor motor, the stator is included internal iron yoke and tooth and hammer pointing outwards designed. In the case of the internal rotor motor, the stator is located on the outside Iron yoke and inward tooth and hammer designed. At the The rotor of the external rotor motor is inside the magnet and the iron yoke Outside. The magnet on the rotor of the inner rotor motor is on the outside and the Iron yoke inside.

3. Commutation device

The motor must be designed with a commutation device that depends on the Position of the rotor chooses the energization scheme of the coils, which the generated maximum moment. The commutation device is usually equipped with Hall Position sensors in combination with a sensor magnet and a MOS-FET Power stage implemented. The Hall position sensors detect the current one Rotor position and control the MOS-FET power amplifier in the required form.

There are many for electronically commutated motors of the type described Combinations of number of poles (2P) and number of slots (n) are known. By choosing pole and slot number, the motor can meet various requirements such as trapezoidal Torque profile, sinusoidal torque profile, low cogging torque, etc. be adjusted. An incline is often used for a particularly low cogging torque proposed by 2π / n of the pole transitions between the magnets.

The main disadvantages of the standard motor design for electronic commutated motors lie in the complex manufacturing processes for the Production of the winding in the internal rotor motor, the lack of a fixed one Housing and the high magnetic costs for the external rotor motor.

The aim of the further development of the motor principle is therefore to have one electronically to design commutated motor that is easy to wind on the one hand and on the other hand has the lower magnetic costs of an internal rotor motor.

Another disadvantage of the standard engine design occurs when operating the engine in the "sensorless" operating mode. The so-called "sensorless" mode of operation relates  that the state of the art works without a Hall element, and that the commutation signal is generated by the induced Voltage in the de-energized phase is measured and as Commutation signal is used, but this is already in the prior art is known.

In this mode of operation, the flow change in the free (not energized) coil generated signal used for commutation. When operating the engine built according to standard design in this operating mode especially in operation with PWM through galvanic, capacitive and inductive Coupling noise signals that the "sensorless" commutation of the motor is essential complicate. The interference signal must either be eliminated electronically or the Signal generation must be avoided by using a suitable motor design.

These basic problems of the standard design are subject to more diverse Patents and publications. The patent US-4,933,585 is intended to represent this be cited. In this patent the use of a concentric Coil suggested. For one phase of the motor there are two in this design Magnetic rings required. The magnetic rings can be part of the stator or part of the Be rotors. Via a flow guide that guides the flow around the concentric coil Depending on the position, the south or north poles of one magnetic ring with the opposite poles of the other magnetic ring connected. For construction An engine requires at least two phases in this design, which must be bidirectionally energized. The design according to patent US-4,933,585 solves the problems of complex winding technology, but it requires twice Magnet volume as the standard design to generate comparable flow. The reason for this is that in each magnetic ring only half of the magnetic volume for Flow generation is used, the other half of the poles short-circuits without going to Contribute useful flow. Another disadvantage of this solution is the complex Rotor construction.

The object of the present invention is now an electronic commutated motor of the type mentioned in such a way that it easier is to be wrapped, compared to the known motors of comparable performance has a smaller volume and the advantages of lower magnet costs Has inner rotor motor.  

To achieve the object, the invention is through the technical teaching of Claim 1 or 16 provided.

The present invention improves the solution according to US Pat. No. 4,933,585 in that by using the north and south poles of a magnet Magnet volume and space for one phase can be halved.

It can be seen from US 4,933,585 that only half of the magnetic poles for the extraction of the magnetic flux is used because with two magnetic rings must be worked.

The solution principle according to the present invention is that only with a single magnetic ring is worked, which has the advantage that the so manufactured engine has a significantly smaller volume.

By using the claw plates according to the invention it is now achieved that the north poles of one magnetic ring with the south poles of the same magnetic ring are interconnected and the flow is thereby directed around the coil.

It follows from this that the generation of the magnetic flux only is achieved by a single magnetic ring, but one from the single Magnetic ring, in principle through the use of claw poles according to the invention, double the number of flux-generating magnets is reached.

So that means that the second magnetic ring is no longer needed and therefore omitted and instead a single magnetic ring in connection with one Flußleitblech and claws arranged thereon is used.

This results in significant advantages because of the construction volume of the engine can be significantly reduced compared to a comparable engine Performance, and that there are much lower manufacturing costs because for the flow guide deep-drawn sheet metal parts can be used.

The proposed design of the Flußleitteile is z in other engine principles. B. Stepper motors known as claw-pole construction. By expanding this Design with electronic commutation is a major improvement the motor parameters possible.  

In other words: the cost-effective production of the claw pole design for the River conduction with the good operating characteristics of an electronic commutated motor combined. Other advantages of the proposed Motor principles are minimized with regard to "sensorless" commutation Interference signals due to the complete decoupling of the motor phases and the very compact design with the resulting high torque at low Dimensions.

The first advantage, a simpler one, results from the present invention Winding the motor because a single, concentric coil is used that is particularly easy to wrap. The other advantage is due to the Using a single magnetic circuit to get lower noise, because the use of a flow baffle with appropriate claws Shielding of the individual phases against each other is given very cheaply that there is crosstalk or overlaying the individual Commutation signals comes.

These advantages result in particular in the so-called "sensorless" configuration, d. that is, if one without Hall elements for generating the commutation signals is working.

Of course, the present invention can also be carried out if one corresponding Hall elements to generate the corresponding Commutation signal used. So there will be both Commutation options claimed.

The phase of the proposed motor is analogous to a claw pole construction built up. For this purpose, a magnet is magnetized alternately with 2P poles. The River bleaching is designed with claws. The claws, preferably in shape of bent sheet metal teeth, repeat themselves at a distance from a pair of poles, d. H. a flow baffle has n claws. The width of a claw is advantageously about ¾ the pole width of the magnet. The flow baffles realize in connection with the flux line around the concentric coil. there is through the first flux baffle the magnetic flux to the north or South Pole of the magnet recorded, passed on via the iron yoke and finally through the second flow baffle with the opposite poles of the Magnets connected.  

The magnetic flux that can be passed through a phase is through the Sheet thickness limited. Is it necessary to have higher magnetic fluxes with the same Winding design (i.e. higher torques), then either Sheet thickness can be increased, or the phase can be installed several times in the motor.

The motor also has an electronic commutation device. Depending on the position of the rotor relative to the stator, this device generates Signals that are used to commutate the motor. By means of these signals the for Realizes a maximum moment required current.

The torque curve depending on the energization of the winding and the position of the rotor has points of intersection at which the sensor system must generate the commutation signals and must switch on the energization to the next energization pattern. The following current sequence must be implemented and repeated for the polarity when energized:
1st phase negative current direction,
2nd phase of positive current direction,
1st phase of positive current direction,
2nd phase of negative current direction.

For the opposite direction of rotation of the motor, the current supply scheme is in apply in reverse order.

The current supply scheme applies to the two-phase motor, an n-phase Execution of the engine principle shown is quite possible. The phases must then be shifted by 2π.n / 2P, where P is the number of pole pairs and n number of the phases.

To operate as an electronically commutated motor, especially if with Block commutation is to be worked, the cogging torques are reduced. This is achieved through the appropriate use of saturation effects or through Slant of the magnetization.

The subject matter of the present invention results not only from the Subject of the individual claims, but also from the combination of individual claims among themselves.  

All information disclosed in the documents, including the summary and features, in particular the spatial depicted in the drawings Education are claimed as essential to the invention, insofar as they are used individually or in Combination are new compared to the prior art.

In the following, the invention will be explained using only one embodiment illustrative drawings explained in more detail. Here go from the drawings and its description further features and advantages of the invention Invention.

Show it:

Fig. 1 section through an engine according to the invention in the direction of line II in Fig. 2;

Fig. 2 section along the line II-II in Fig. 1;

Fig. 3, the unwound magnetic poles from the magnetic ring 5;

Fig. 4, the illustration of Polausprägung arising on the claws of the Flußleitbleche,

Fig. 5, the mechanical torque action of the rotor when current flows through the coil in the corresponding barrel;

Fig. 6 shows the cogging moments that result in de-energized phases or windings.

In Fig. 1 and 2, such a motor is generally shown, which consists essentially of an outer back iron ring 1, the fully circumferentially encloses the motor on its outer periphery.

The concentrically wound coil 6 is arranged radially inward and is laterally encompassed on the flanks by lateral flux guide plates 2 , 3 .

It is essential that the flow guide plates 2 , 3 each form an outer circumferential ring located on the flank, so that the coil 6 is located laterally between self-contained flow guide plates 2 , 3 and each flow guide plate 2 , 3 axially extending claws 4 , 8 , which claws extend over the longitudinal center line according to FIG. 2, here the magnetic flux from the iron at position 10 is to be picked up and passed over the flux guide plate 3 in the direction of arrow 11 to the iron return ring 1 and from here in the direction of arrow 12 the flow guide plate 2 and then finally on the claw 4 of the flow guide plate 2 .

This results in a completely closed flow circle, which is supplemented by the claws 4 , 8 arranged distributed around the circumference.

The inner magnetic ring 5 consists of alternately magnetized permanent magnets, so that north and south polarizations abut one another, the number of pole pairs corresponding to the number of claws. This means that two claws 4 , 8 are responsible for a single north-south permanent magnet.

It should also be noted that the inner iron return ring 7 the flow of z. B. a north polarized permanent magnet leads to the adjacent south pole of the adjacent permanent magnet.

In addition, the motor has an inner recess 9 through which a drive shaft extends. It should be noted that the representation of FIGS. 1 and 2 shows only a single phase of a multi-phase, electronically commutated motor. That is, the other phase of the motor is designed in an identical manner to the motor according to FIGS. 1 and 2, wherein an offset of half a pole width is required in a two-phase arrangement and in a three-phase arrangement, an offset of a third pole width .

In the case of a multi-phase arrangement, the illustration according to FIG. 1 and FIG. 2 is exactly multiplied, that is to say these lie one behind the other on a common shaft. Each phase is then assigned exactly the parts as explained using a phase according to FIGS. 1 and 2.

One can also arrange and control several such units according to FIGS. 1 and 2 directly behind one another and adjacent to one another on a common shaft in a single-phase motor, but the spatial angular displacement between the individual units is eliminated, i.e. a single phase of the motor then by one A plurality or plurality of such aggregates according to FIGS. 1 and 2 is formed.

In FIGS. 3 to 6, the transactions are now shown of such a motor, where 3 is the handling of the magnet ring is shown in Fig. To level 5, while Fig. 4 shows in the upper diagram, how the representation of the poles of the Flußleitbleche 2 , 3 are handled with their claws 4 , 8 on the same level. This applies to one phase of the engine.

If, on the other hand, a two-phase motor is to be created, it was stated above that the same unit according to FIGS. 1 and 2 must then be present again, which is arranged offset from the first unit at a certain angle of rotation. This is shown in Fig. 4 in the lower representation, where it is shown that when a second phase is added, the development of the claw poles of this second phase then result in the arrangement shown.

Here, the north and south poles are always put in brackets below, which means that if one phase (see Fig. 4, upper illustration) is flowed through in one direction, then the south and north poles in the notation shown 4, meanwhile, if the one phase in the upper illustration according to FIG. 4 is energized in the opposite direction, then the north and south poles result in brackets.

The same applies to the illustration in FIG. 4 below, where the current supply in one direction (with unclamped north and south poles) is shown for the second phase, while the current supply in the other direction results in the orientation of the magnets in parentheses .

FIG. 5 shows a total of the torque effect without drawn detent torques of the phases being illustrated, the phases for the first phase for positive and negative current flow in a total of four different representations, while in another representation of negative, the torque effects in the second phase, in turn, with positive and Current supply are shown.

It can be seen here that the representation of the moment effect via the mechanical development for a positive energization of the first phase is denoted by 13 , while the negative energization of this first phase is denoted by 14 .

If a second phase is added (see description above), then the moment effect 16 results in the case of positive energization and the moment effect 15 in the case of negative energization (see also the drawing legend for FIG. 5).

It can be seen from this that the current supply is switched at the commutation points 17 , and thereby a largely constant torque is achieved, as can be seen overall from the line 18 , which is shown relatively without significant fluctuation.

In Fig. 6, the cogging torques are shown, which result from the fact that when the phase is not energized, the permanent magnets align themselves with the flux guide plates and develop a certain cogging torque there. This cogging torque should be kept as low as possible and this cogging torque is very small in accordance with the chosen design measures according to the invention, so that the motor runs with a low cogging torque.

The invention is therefore that the arrangement of each end Flußleitblechen is provided for an electronically commutated motor, which limit the coil on the flank side, each with axially extending to the coil and offset from one another on the inner circumference of the annular flow guide plates arranged and interdigitated claws.  

Drawing legend

1

Iron yoke ring (outside)

2nd

Flow baffle

3rd

Flow baffle

4th

Claw (flow baffle

2nd

)

5

Magnetic ring

6

Kitchen sink

7

Iron yoke ring (inside)

8th

Claw (flow baffle

3rd

)

9

Recess

10th

position

11

Arrow direction

12th

Arrow direction

13

Moment effect

14

Moment effect

15

Moment effect

16

Moment effect

17th

Commutation point

18th

line

Claims (16)

1. Electronically commutated electric motor, consisting of n strands, a strand consisting of a stator with an iron return ring ( 1 ) and a concentric coil ( 6 ), a rotor with an iron return ring ( 7 ) and at least one permanent magnet, characterized in that the / the Permanent magnets of the rotor form only a single magnetic ring ( 5 ), or is made up of individual segments, the north and south poles of the / the permanent magnet abutting and additionally in the stator flux baffles ( 2 , 3 ) are present, which are the magnetic flux of the north and south poles Connect the permanent magnet (s) of the magnetic ring ( 5 ) to one another. 2. Electronically commutated electric motor according to claim 1, characterized in that the flux guide plates ( 2 , 3 ) are attached to at least one of the two end flanks of the concentric coil ( 6 ) and / or the iron yoke ring ( 1 ). 3. Electronically commutated electric motor according to one of claims 1 or 2, characterized in that the flux guide plates ( 2 , 3 ) have claws ( 4 , 8 ), which claws ( 4 , 8 ) substantially in the vicinity of the poles of the permanent magnet ring ( 5 ) lie. 4. Electronically commutated electric motor according to one of claims 1 to 3, characterized in that the claws ( 4 ) of the first flux guide plate ( 2 ) cooperate with the poles of the permanent magnet ring ( 5 ) which are poled differently, as the claws ( 8 ) of the second flow baffle ( 3 ). 5. Electronically commutated electric motor according to one of claims 1 to 4, characterized in that the flux guide plates ( 2 , 3 ) each form a circumferential ring. 6. Electronically commutated electric motor according to claim 5, characterized in that the claws ( 4 , 8 ) on the inner circumference of the flux guide plates ( 2 , 3 ) are arranged. 7. Electronically commutated electric motor according to one of claims 1 to 6, characterized in that the claws ( 4 , 8 ) of the flux guide plates ( 2 , 3 ) have a substantially circular segment shape. 8. Electronically commutated electric motor according to one of claims 1 to 7, characterized in that the claws ( 4 ) of the flux guide plate ( 2 ) and the claws ( 8 ) of the flux guide plate ( 3 ) offset at an angle to one another on the end face of the coil ( 6 ) and / or the flow guide plate ( 1 ) are arranged. 9. Electronically commutated electric motor according to claim 8, characterized in that the claws ( 4 ) of the flux guide plate ( 2 ) and the claws ( 8 ) of the flux guide plate ( 3 ) overlap at a distance from one another in the direction of the motor axis. 10. Electronically commutated electric motor according to one of claims 1 to 9, characterized in that the claws ( 4 , 8 ) of the flux guide plates ( 2 , 3 ) essentially between the poles of the permanent magnet ring ( 5 ) and the concentric coil ( 6 ) lie. 11. Electronically commutated electric motor according to one of claims 1 to 10, characterized in that the claws ( 4 , 8 ) of the flux guide plates ( 2 , 3 ) essentially on a to the coil ( 6 ) and / or to the permanent magnet ring ( 5 ) concentric circle. 12. Electronically commutated electric motor according to one of claims 1 to 11, characterized in that the iron yoke ring ( 1 ) of the stator is located radially outside the concentric coil ( 6 ). 13. Electronically commutated electric motor according to one of claims 1 to 12, characterized in that the iron yoke ring ( 9 ) of the rotor lies radially inward to the permanent magnet ring ( 5 ). 14. Electronically commutated electric motor according to one of claims 1 to 13, characterized in that with a number of n coils ( 6 ) or phases these are arranged offset from one another on the stator by an angle of π.n / number of pole pairs. 15. Electronically commutated electric motor according to one of claims 1 to 13, characterized in that several electric motors are arranged with their recess ( 9 ) on a common shaft and the coils ( 6 ) have no angular offset and thus form a common phase. 16. Electronically commutated electric motor, consisting of n strands, a strand consisting of a stator with an iron return ring ( 1 ) and a concentric coil ( 6 ), a rotor with an iron return ring ( 7 ) and at least one permanent magnet, characterized in that the / the Permanent magnet / s of the rotor only form a single magnetic ring ( 5 ), or is made up of individual segments, the north and south poles of the permanent magnet (s) abutting each other and additionally in the stator there are flux baffles ( 2 , 3 ) which provide the magnetic Connect the flux of the north and south poles of the / the permanent magnet (s) of the magnetic ring ( 5 ) and the circle segment length and the axial width of the claws ( 4 , 8 ) about 3/4 of the circle segment length and the axial width of the respective North or south pole of the magnet (s) is 5 .