JP2021166450A - Brushless motor and brushless motor control method - Google Patents

Abstract

To suppress vibration or operation sound in a brushless motor with a (10 P12S)×n or (14 P12S)×n configuration having a two-system field magnet winding.SOLUTION: A brushless motor 1 includes a stator 2 and a rotor 3. The stator 2 comprises: 12×n teeth 5; and coils 7 with a plurality of phases. The rotor 3 has 10×n or 14×n magnets 12. The coils 7 form two-system field magnet windings A and B. Coils 7 forming the same phase are grouped, and the coils 7 are set at positions where they are adjacent to or overlap each other at an electric angle. Also, the teeth 5 on which the coils 7 at the positions are wound are arranged at the stator 2 at a mechanical angle corresponding to the electric angle. Then, the coils 7 are divided into two systems and the two-system field magnet windings are energized with a predetermined phase difference.SELECTED DRAWING: Figure 3

Description

The present invention relates to a brushless motor having two field windings, and more particularly to a brushless motor in which 10 × n or 14 × n magnets are arranged for 12 × n teeth.

Vehicle motors such as electric power steering motors are required to have low torque ripple and low cogging performance in addition to small size and high output. For this reason, in vehicle motors, as one of the means for achieving these goals, the motor has conventionally been configured to have a 10-pole 12-slot or a 14-pole 12-slot configuration. Further, vehicle motors for automobiles and the like are required to have not only the above performance but also high safety. Therefore, in such a motor, by changing the function of only one system to an independent multiple system, it is becoming important to have redundancy to continue the function in another system even if one system fails. There is.

FIG. 14 is an explanatory diagram showing a configuration of a conventional vehicle (for electric power steering device) motor. The brushless motor 51 of FIG. 14 includes a stator 52 and a rotor 53 rotatably arranged in the stator 52. Ten magnets 54 are attached to the rotor 53. Further, the teeth 55 are projected from the stator 52 along the radial direction, and the brushless motor 51 is abbreviated as 10P12S with 10 poles and 12 slots (hereinafter, the number of magnetic poles is P and the number of slots is S). ) It is composed. Each tooth 55 is wound with a coil 56 that forms a U, V, and W three-phase field winding.

In the brushless motor 51, the field windings are divided into two systems (A and B), and the coils 56 are also provided with each phase for each system (56AU: A system / U phase, 56BU: B system, U phase, etc.). In the figure, the coil 56 having a negative sign (minus) indicates that the winding direction to the teeth 55 is opposite to that of the coil 56 having no symbol of the same system and the same phase. In such a brushless motor 51, the coils 56 of each phase of both the A and B systems are sequentially energized, so that the magnet 54 is attracted to the excited teeth 55, and the rotor 53 rotates. At that time, since the coil 56 is composed of two different systems, even if one system fails, the operation of the motor is ensured by the coils of the other system.

Japanese Unexamined Patent Publication No. 2005-237068

However, in the case of a brushless motor having a configuration as shown in FIG. 14, two adjacent teeth facing each other at a mechanical angle of 180 ° have the same phase. That is, for example, the teeth 55 wound with the coils 56AU, −56AU and the coils 56BU, −56BU (combination surrounded by a broken line in the drawing) in FIG. 14 have the same phase. For this reason, there is a problem that an electromagnetic excitation force in the direction indicated by the arrow is applied when the coil is energized, and the stator 52 is deformed into an elliptical shape in the vibration mode of the secondary ring, which contributes to vibration and noise. In particular, when it resonates with the natural frequency of the motor, there is a possibility that a large vibration will occur.

An object of the present invention is to reduce the electromagnetic excitation force in a brushless motor in which 10 × n or 14 × n magnets are arranged for 12 × n teeth, and to suppress vibration and operating noise of the motor. It is in.

The brushless motor of the present invention has a stator and a rotor arranged inside the stator in the radial direction, and the stator is wound with 12 × n teeth and a concentrated winding around the teeth. A brushless coil comprising a multi-phase coil, the rotor comprising 10 × n or 14 × n magnets, the coil forming two field windings that are energized as separate systems. The coil, which is a motor (n is a positive integer) and forms the same phase, is grouped, the coil is set at an adjacent or overlapping position by an electric angle, and the coil at that position is wound. The teeth are arranged on the stator at a mechanical angle corresponding to the electric angle, the coil is divided into the two systems, and the field windings of the two systems are energized with a predetermined phase difference. It is characterized by that.

In the present invention, in a brushless motor having a (10P12S) × n or (14P12S) × n configuration equipped with two field windings, coils having the same phase are arranged adjacent or overlapping at an electric angle. At the same time, the teeth around which the coil is wound are arranged at a mechanical angle corresponding to the electric angle. As a result, the teeth are arranged so that the two adjacent teeth facing each other at a mechanical angle of 180 ° are not in phase with each other. Further, while adopting such a teeth arrangement, the two in-phase coils are energized with a predetermined phase difference to compensate for the angular difference in the vector of the induced voltage generated in the teeth by the coils of different in-phase systems.

In the brushless motor, the stator has 12 teeth, the rotor has 10 or 14 magnets, the coil is energized with a three-phase current, and the teeth have four adjacent teeth. The coils of the same phase are wound as one group, and two adjacent coils of the teeth in the same phase belong to each system of the field windings, and two systems of the field windings are used. May be energized with a phase difference of 60 °.

Further, in the brushless motor, the stator includes 12 teeth, the rotor includes 10 or 14 magnets, the coil is energized with a three-phase current, and the teeth are adjacent to the teeth. When the coils are wound so as to be out of phase with each other and the three adjacent teeth belonging to different phases are grouped into one group, the coils of the two adjacent teeth in the group are said to be the above 2. The coil of the remaining one of the teeth belongs to one of the field windings of the system, belongs to the other system of the two systems, and the field winding of the two systems. The wire may be energized with a phase difference of 60 °.

Further, in the brushless motor, the stator has 12 teeth, the rotor has 10 or 14 magnets, the coil is energized with a three-phase current, and the teeth have three adjacent teeth. The coils having the same phase are wound as one group, and the coils arranged between the adjacent groups are wound with the coils having a phase different from that of the groups on both sides. The coil of the tooth in the coil has two adjacent coils belonging to one of the two fields of the field winding, and is arranged between the remaining one in the group and the group of the other phase. The coil of one of the teeth belongs to the other system of the two systems, and the field windings of the two systems may be energized with a phase difference of 30 °.

On the other hand, the brushless motor control method of the present invention includes a stator and a rotor arranged radially inside the stator, and the stator has 12 × n teeth and a concentrated winding around the teeth. It comprises a wound multi-phase coil, the rotor comprises 10 × n or 14 × n magnets, and the coil forms two systems of field windings that are energized as separate systems. This is a method for controlling a brushless motor (n is a positive integer), in which the coils forming the same phase are grouped, the coils are set at adjacent or overlapping positions by electrical angle, and the above-mentioned positions are set. The teeth around which the coil is wound are arranged on the stator at a mechanical angle corresponding to the electric angle, the coil is divided into the two systems, and a predetermined value is provided for the field windings of the two systems. It is characterized by energizing with a phase difference.

In the present invention, in a brushless motor having a (10P12S) × n or (14P12S) × n configuration equipped with two field windings, coils having the same phase are arranged adjacent or overlapping at an electric angle. At the same time, the teeth around which the coil is wound are arranged at a mechanical angle corresponding to the electric angle. As a result, the teeth are arranged so that the two adjacent teeth facing each other at a mechanical angle of 180 ° are not in phase with each other. Further, while adopting such a teeth arrangement, the two in-phase coils are energized with a predetermined phase difference to compensate for the angular difference in the vector of the induced voltage generated in the teeth by the coils of different in-phase systems.

According to the brushless motor of the present invention, in a brushless motor having a (10P12S) × n or (14P12S) × n configuration having two field windings, coils having the same phase in an adjacent or overlapping manner at an electric angle are formed. While arranging, the teeth around which the coil was wound were arranged at a mechanical angle corresponding to the electric angle, and the two in-phase coils were energized with a predetermined phase difference, so that the mechanical angle was 180. ° The teeth are arranged so that the two adjacent teeth that face each other are not in phase, and further, it is possible to energize in a form that compensates for the angular difference in the vector of the induced voltage generated in the teeth by coils of different systems of the same phase. Therefore, the teeth facing 180 ° at the mechanical angle are not excited at the same time, and the electromagnetic excitation force in the radial direction is not applied when the coil is energized, so that the vibration and noise of the motor can be suppressed.

Further, according to the brushless motor control method of the present invention, in a brushless motor having a (10P12S) × n or (14P12S) × n configuration provided with two field windings, they are adjacent to each other or overlap each other in terms of electrical angle. While arranging the in-phase coils, the teeth around which the coils were wound were arranged at the mechanical angle corresponding to the electric angle, and the two in-phase coils were energized with a predetermined phase difference. The teeth are arranged so that the two adjacent teeth facing each other by 180 ° at the mechanical angle are not in phase, and the energization is performed in a form that compensates for the angle difference of the induced voltage vector generated in the teeth by the coils of different systems of the same phase. It will be possible. Therefore, the teeth facing 180 ° at the mechanical angle are not excited at the same time, and the electromagnetic excitation force in the radial direction is not applied when the coil is energized, so that the vibration and noise of the motor can be suppressed.

It is explanatory drawing which shows the structure of the brushless motor which is Embodiment 1 of this invention. It is explanatory drawing which shows the phase arrangement in the brushless motor of the 10P12S configuration. It is explanatory drawing which shows the phase arrangement in the brushless motor which is Embodiment 1 of this invention. It is explanatory drawing which shows the induced voltage vector of the U phase in the brushless motor of FIG. It is explanatory drawing which compared the relationship between a rotor rotation angle and torque with a conventional motor and the motor by this invention. It is explanatory drawing which compared the conventional motor and the motor by this invention about the average torque and torque ripple. It is explanatory drawing which shows the excitation frequency response analysis result by the electromagnetic force of the conventional motor and the motor by this invention, and shows the relationship between a rotation order and an acceleration amplitude. It is explanatory drawing which took out and compared the component of the 10th order, the 50th order, the 70th order, and the 71st order from the result of FIG. (A) and (b) are explanatory views showing the phase arrangement in the brushless motor which is Embodiment 2 of this invention, and (c) is explanatory drawing which shows the structure of the brushless motor. It is explanatory drawing which shows the induced voltage vector of the U phase in the brushless motor of FIG. (A) and (b) are explanatory views showing the phase arrangement in the brushless motor which is Embodiment 3 of this invention, and (c) is explanatory drawing which shows the structure of the brushless motor. It is explanatory drawing which shows the induced voltage vector of the U phase in the brushless motor of FIG. It is explanatory drawing which shows an example of the phase arrangement when this invention is applied to the brushless motor of 14P12S, (a) is Embodiment 1, (b) is Embodiment 2, (c) is Embodiment 3. The arrangements correspond to each. It is explanatory drawing which shows the structure of the conventional brushless motor for a vehicle.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing a configuration of a brushless motor 1 (hereinafter, abbreviated as motor 1) according to the first embodiment of the present invention. As shown in FIG. 1, the motor 1 has an inner rotor type configuration in which a rotor (rotor) 3 is rotatably arranged inside a stator (stator) 2 like the motor 51 of FIG. For example, it is used as a drive source for an electric power steering device.

The stator 2 is fixed to the inside of a bottomed cylindrical motor case 4 made of iron or the like by press-fitting or fixing means such as an adhesive. The stator 2 has a stator core 6 provided with teeth 5 and a coil 7 wound around the teeth 5 by centralized winding. The stator core 6 is formed by laminating thin plate materials such as electromagnetic steel plates, and a plurality of (12 in this embodiment) teeth 5 are projected inward in the radial direction. Slots 8 are formed between the adjacent teeth 5, and the stator 2 has a 12-slot configuration.

Also in the motor 1, the coil 7 forms a three-phase field winding of U, V, and W. Similar to the motor 51 in FIG. 14, the field windings of the motor 1 are also divided into two parallel systems (A and B), and each coil 7 has two fields energized as separate systems. It forms a winding. The coil 7 is also provided with a coil of each phase for each energization system (7AU: A system / U phase, 7BU: B system / U phase, etc.).

A rotor 3 is inserted inside the stator 2. The rotor 3 has a rotor shaft (rotating shaft) 9, and is rotatably supported by bearings (not shown). The rotor 3 includes a columnar rotor core 11 made of a magnetic material, and a plurality of magnets 12 arranged at equal intervals along the circumferential direction on the outer periphery of the rotor core 11. The rotor core 11 is also formed by laminating thin plate materials such as electromagnetic steel plates, and is fixed to the outer periphery of the rotor shaft 9. The magnet 12 is a substantially rectangular parallelepiped permanent magnet, magnetized along the radial direction, and arranged so that the polarities of adjacent magnets 12 are different from each other. Ten magnets 12 are provided here, and the rotor 3 has a 10-pole configuration. A cover 13 for preventing scattering is attached to the outside of the magnet 12.

Here, in the motor 1, the mechanical angle between the adjacent teeth 5 is 360 ° / 12 = 30 °. On the other hand, since the motor 1 has a 10-pole configuration, the number of pole pairs is 5, and the electric angle between the adjacent teeth 5 is 5 (pole logarithm) × 30 ° (mechanical angle) = 150 °. That is, when the teeth 5 are numbered (1) to (12) as shown in FIG. 2 (a), for example, the teeth 5a of (1) and the teeth 5b of (2) have a mechanical angle. The relationship is 30 ° and 150 ° in terms of electrical angle. Therefore, when the induced voltage generated in each coil 7 is considered and indicated by an arrow (vector) extending radially outward from the center of the circle, as shown in FIG. 2 (b), the tooth 5a of (1) is used as a reference. Then, each vector is arranged in the form of (2), (3), and so on at intervals of 150 °.

Next, when the vector of FIG. 2B is divided for each phase and the coils 7 of the opposite group on one side are wound in the opposite direction, the vector of the teeth 5 on which the reverse winding coil 7 is wound is shown in FIG. It faces in the opposite direction to the vector in (b). Fig. 2 (c) summarizes this vector with a negative (-: minus) sign, (7), (12), (3), (8), (4), (11). The vectors of are reversed and they are moved and described. In FIG. 2C, the two vector directions having a 120 ° phase are grouped into three groups (U, V, W), and when the windings are set in this form, they face each other by 180 ° in mechanical angle as shown in FIG. A field winding in which two adjacent teeth are in the same phase is formed.

However, when the winding form as shown in FIG. 14 is adopted, as described above, there is a problem that an electromagnetic excitation force in the opposite direction is applied when the coil is energized, which contributes to vibration and noise. On the other hand, in the motor 1 according to the present invention, as shown in FIG. 3A, the four vector directions having a 120 ° phase are grouped into three groups. 3A and 3B are explanatory views showing the phase arrangement process in the motor 1, and FIG. 3C is an explanatory view showing the phase arrangement of the motor 1. Here, from the vectors of FIG. 2 (b), the vectors of (1), (3), (5), (7), (9), and (11) are set to minus, and the adjacent four vectors are set to one group. .. When this is assigned to each phase and arranged on the teeth 5, the shape is as shown in FIG. 3 (b), and further, when it is a two-system winding (A, B), each tooth 5 and the coil 7 are shown in FIG. 3 (c). ) Is the phase arrangement.

In this case, the teeth 5 are wound with coils 7 having the same phase, with four adjacent coils as one group. Further, the coils 7 wound around the four teeth 5 in the same phase have two adjacent coils belonging to each of the two systems. That is, as shown in FIG. 3C, for example, the teeth 5e to 5h of Nos. (5) to (8) form one group, and the U-phase coils 7AU and 7BU are wound. At that time, coils 7AU and 7BU belonging to different systems A and B are wound around the two adjacent teeth 5g and 5h and the teeth 5e and 5f in the U phase.

As is clear from FIG. 3C, by adopting such a winding configuration, the motor 1 has a phase arrangement in which two adjacent teeth facing each other at a mechanical angle of 180 ° are not in phase with each other. Therefore, an electromagnetic excitation force in the radial direction is applied when the coil is energized, and the stator 2 is not deformed into an elliptical shape in the ring secondary vibration mode, so that vibration and noise of the motor can be suppressed. Further, in a split core motor having a 12-slot structure, it is usually necessary to perform welding at 24 points when connecting the coil of each split core and the bus bar (not shown), but the coil arrangement of the motor 1 is shown in FIG. As shown in c), two in-phase segments are paired. As a result, it is possible to use a unit in which two segments are continuously wound, and it is possible to reduce the number of welded parts, reduce the number of layers of the bus bar, and shorten the shaft of the motor.

On the other hand, in the winding configuration as shown in FIG. 3C, the vectors of each phase are displaced by 60 ° between the A and B2 systems. FIG. 4 is an explanatory diagram showing a U-phase induced voltage vector. As shown in FIG. 4, in the U phase, the composite vector Vua of (8) and − (7) is generated in the A system, and the composite vector Vub of (6) and − (5) is generated in the B system, and these are synthesized. The angle between the vectors Vua and Vub is 60 °.

Therefore, in the motor 1 according to the present invention, the windings (A, B) of the two systems are energized with a phase difference of 60 °, which is the same as the angle difference of the vectors, in accordance with the generation timing of both vectors. As a result, in each phase, the windings of the two systems are smoothly and sequentially excited. At that time, in the motor 1, as can be seen from FIG. 3C, the teeth 5 of each phase are adjacent to each other in the same phase, and the two adjacent teeth facing 180 ° do not have the same phase. .. Therefore, as in the configuration of FIG. 14, when the coil is energized, the electromagnetic excitation force in the opposite direction is not applied, and the generation of vibration and noise is suppressed.

FIG. 5 is an explanatory diagram comparing the relationship between the rotor rotation angle and torque between a conventional motor (FIG. 14) and the motor according to the present invention, and FIG. 6 is an explanatory diagram comparing them with respect to average torque and torque ripple. .. Further, FIG. 7 is an explanatory diagram showing the result of vibration frequency response analysis by the electromagnetic force of the conventional motor (FIG. 14) and the motor according to the present invention, and shows the relationship between the rotation order and the acceleration amplitude. Further, FIG. 8 is an explanatory diagram in which the 10th, 50th, 70th, and 71st order components are extracted from the results of FIG. 7 and compared. In this case, FIGS. 5 and 6 show the stator outer diameter 56 mm, rotor outer diameter 28.5 mm, magnet; Nd-Fe-B sintered magnet, stator shaft length 35 mm, winding specifications: φ1.0 mm × 20 turns (2 series). This is the result under the conditions of (2 systems of Y connection) and a phase current of 14.1 Arms (id = 0A). In addition, FIGS. It should be noted that FIGS. 5 to 8 also show the results of the cases 2 and 3 described later, in which (a) is the case of the first embodiment and (b) is the case of the second embodiment. , (C) show the case of the third embodiment, and (p) show the case of the conventional motor.

As shown in FIGS. 5 and 6, the torque ripple of the motor 1 is slightly lower than that of the motor 1, but the conventional motor and the motor 1 are almost the same in both cases (in FIG. 5, the motor 1 is the same). It is almost the same as a motor and a conventional motor, and cannot be distinguished on the graph). Next, regarding the acceleration amplitude, as shown in FIGS. 7 and 8, the acceleration amplitudes of the 50th and 71st orders of the motor 1 are smaller than those of the conventional ones. In particular, the 71st order is significantly reduced, and the resonance of the stator is suppressed to be small. The acceleration amplitudes of FIGS. 7 and 8 can be said to be alternative characteristics of the motor vibration, and from the analysis results, it can be seen that the vibration and the operating noise of the motor 1 are reduced as compared with the conventional motor.

As described above, the motor 1 according to the present invention is a brushless motor having a 10P12S configuration equipped with two field windings, in which the teeth 5 and the coil 7 having the same phase are arranged adjacent to each other at the electric angle, and the mechanical angle is increased. The teeth 5 are arranged so that the two adjacent teeth facing each other at 180 ° are not in phase with each other. Then, the two in-phase coils 7 are energized with a phase difference corresponding to the angle difference of the vector of the induced voltage generated in the teeth 5 by the coils 7 of different in-phase systems.

By the phase difference energization of these two systems, in the motor 1, each phase coil of the two systems is sequentially and smoothly excited according to the angle difference of the induced voltage vector, and at that time, the teeth 5 facing 180 ° at the mechanical angle are simultaneously excited. Not excited. Therefore, the radial electromagnetic excitation force is not applied when the coil is energized, and the vibration and noise of the motor can be suppressed. Therefore, when the motor 1 is used as the drive source of the power steering device, vibration transmitted from the motor 1 to the driver via the steering wheel, motor operating noise during steering, and the like are suppressed, and the steering feeling is improved. ..

(Embodiment 2)
Next, the brushless motor 21 (hereinafter, abbreviated as motor 21) according to the second embodiment of the present invention will be described. The basic configuration of the motor 21 is the same as that of the motor 1 described above, but the phase arrangement of the teeth 5 and the coil 7 is different from that of the first embodiment. The same parts and members as those of the motor 1 of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

9 (a) and 9 (b) are explanatory views showing the phase arrangement process in the motor 21, and FIG. 9 (c) is an explanatory view showing the configuration of the motor 21. Here, from the vectors of FIG. 2B, for example, (1), (6), (8), and (11) are in phase, and four adjacent vectors are grouped. As a result, three groups in four vector directions having a phase of 120 ° are formed. When this is assigned to each phase and arranged on the teeth 5, the shape is as shown in FIG. 9 (b), and further, when it is a two-system winding (A, B), each teeth 5 and the coil 7 are shown in FIG. 9 (c). ).

In this case, the coil 7 is wound around the teeth 5 so that the adjacent teeth are out of phase with each other. Further, when three adjacent teeth 5 belonging to different phases are grouped into one group, the coil 7 of the two adjacent teeth 5 in this group is one of the two field windings A and B. The coil 7 of the remaining one tooth 5 in the group belongs to the other system of the two systems.

That is, as shown in FIG. 9C, for example, the teeth 5a to 5c of Nos. (1) to (3) are wound with coils 7 having different phases U, V, and W, respectively. Further, when three adjacent teeth 5a, 5b, 5c belonging to different phases U, V, W are grouped into one group, the coils 7 of the two adjacent teeth 5b, 5c in this group are two systems. (7AV, 7AW) belongs to one of the field windings A and B, and the coil 7 of the remaining one tooth 5a in the group belongs to the other system B of the two systems. (7BU).

As is clear from FIG. 9C, by adopting such a winding configuration, the motor 21 has a phase arrangement in which two adjacent teeth facing each other at a mechanical angle of 180 ° are not in phase with each other. Therefore, an electromagnetic excitation force in the radial direction is applied when the coil is energized, and the stator 2 is not deformed into an elliptical shape in the ring secondary vibration mode, so that vibration and noise of the motor can be suppressed.

As shown in FIG. 10, even in the winding configuration as shown in FIG. 9C, the vector of each phase is shifted by 60 ° between the two systems A and B. That is, for example, in the U phase, the composite vector Vua of (1) and (8) is generated in the A system, the composite vector Vub of (6) and (11) is generated in the B system, and between these composite vectors Vua and Vub. The angle of is 60 °. Therefore, as described above, also in the motor 21, the windings (A, B) of the two systems are energized with a phase difference of 60 ° to synchronize the generation times of both vectors. As a result, in each phase, the windings of the two systems are excited without any phase difference. Also in this case, in the motor 21, as can be seen from FIG. 9C, the teeth 5 of each phase are adjacent to each other in the same phase, and the two adjacent teeth 5 facing each other by 180 ° may be in the same phase. No. Therefore, as in the configuration of FIG. 14, when the coil is energized, the electromagnetic excitation force in the opposite direction is not applied, and the generation of vibration and noise is suppressed.

As shown in FIGS. 5 and 6, also in the motor 21, although the torque ripple is slightly lower in the motor 21 in terms of torque and torque ripple, the conventional motor and the motor are almost the same. On the other hand, regarding the acceleration amplitude, as shown in FIGS. 7 and 8, the acceleration amplitude of the 50th and 71st orders of the motor 21 is smaller than that of the conventional motor 21. In this case as well, the 71st order is significantly reduced, the resonance of the stator is suppressed to a small value, and vibration and operating noise are reduced as compared with the conventional motor. Therefore, vibration transmitted from the motor 21 to the driver via the steering wheel, motor operating noise during steering, and the like are suppressed, and the steering feeling is improved.

(Embodiment 3)
Further, a brushless motor 31 (hereinafter, abbreviated as motor 31) according to the third embodiment of the present invention will be described. The basic configuration of the motor 31 is the same as that of the motor 1 described above, but the phase arrangement of the teeth 5 and the coil 7 is different from that of the first and second embodiments. 11 (a) and 11 (b) are explanatory views showing the phase arrangement process in the motor 31, and FIG. 11 (c) is an explanatory view showing the configuration of the motor 31. Here, from the vectors of FIG. 2B, for example, (1), (6), − (7), and (8) are in phase, and four adjacent / overlapping vectors are grouped together. As a result, three groups in three vector directions having a phase of 120 ° are formed. When this is assigned to each phase and arranged on the teeth 5, the shape is as shown in FIG. 11 (b), and further, when it is a two-system winding (A, B), each tooth 5 and the coil 7 are shown in FIG. 11 (c). ).

In this case, the teeth 5 are wound with coils 7 having the same phase, with three adjacent coils as one group. Further, a coil 7 having a phase different from that of the groups on both sides is wound around one tooth 5 arranged between adjacent groups. On top of that, the coil 7 of the teeth 5 in each group has two adjacent coils belonging to one of the two field windings A and B, and the remaining one in the group and the other phase group. The 7 coils of one tooth 5 arranged between the two belong to the other of the two systems.

That is, as shown in FIG. 11 (c), for example, the U-phase coils 7 are wound around the three adjacent teeth 5f to 5h of (6) to (8) as one group Gu. Further, a coil 7 having a phase different from that of the group Gv and Gw on both sides is wound around one tooth 5a arranged between two adjacent groups of the V-phase group Gv and the W-phase group Gw. On top of that, the two adjacent teeth 5g, 5h coils 7 in the group Gu belong to one of the two field windings A and B (coil 7AU), and the rest in the group Gu. The coil 7 of one tooth 5a arranged between the one tooth 5f and the groups Gv and Gw belongs to the other system B of the two systems (coil 7BU).

As is clear from FIG. 11C, by adopting such a winding configuration, the motor 31 has a phase arrangement in which two adjacent teeth facing each other at a mechanical angle of 180 ° are not in phase with each other. Therefore, an electromagnetic excitation force in the radial direction is applied when the coil is energized, and the stator 2 is not deformed into an elliptical shape in the ring secondary vibration mode, so that vibration and noise of the motor can be suppressed.

As shown in FIG. 12, in the winding configuration as shown in FIG. 11C, the vectors of the respective phases are displaced by 30 ° between the A and B2 systems. That is, for example, in the U phase, the composite vector Vua of (8) and − (7) is generated in the A system, the composite vector Vub of (1) and (6) is generated in the B system, and the composite vectors Vua and Vub of these are generated. The angle between them is 30 °. Therefore, in this case, the windings (A, B) of the two systems are energized with a phase difference of 30 ° to synchronize the generation times of both vectors. As a result, in each phase, the windings of the two systems are excited without any phase difference. Also in this case, in the motor 31, as can be seen from FIG. 11C, the teeth 5 of each phase are adjacent to each other in the same phase, and the two adjacent teeth 5 facing each other by 180 ° may be in the same phase. No. Therefore, as in the configuration of FIG. 14, when the coil is energized, the electromagnetic excitation force in the opposite direction is not applied, and the generation of vibration and noise is suppressed.

As shown in FIGS. 5 and 6, the average torque of the motor 31 is almost the same as that of the conventional motor, but the torque ripple of the motor 31 is about 8.2% lower. On the other hand, regarding the acceleration amplitude, as shown in FIGS. 7 and 8, the acceleration amplitudes of the 10th, 50th, and 71st orders of the motor 31 are smaller than those of the conventional ones. However, the 70th-order component is larger than before. In this case, the 70th-order component is large, but the other three components are small. Therefore, the motor 31 has a smaller acceleration amplitude as a whole, and vibration and operating noise are reduced as compared with the conventional motor. Therefore, vibration transmitted from the motor 31 to the driver via the steering wheel, motor operating noise during steering, and the like are suppressed, and the steering feeling is improved.

It goes without saying that the present invention is not limited to the above-described embodiment and can be variously modified without departing from the gist thereof.
For example, the number of pole slots in the brushless motor described above is an example, and the present invention can be applied to motors other than the 10P12S configuration. That is, it can be applied to the brushless motor 41 of 14P12S as shown in FIG. 13 in the same phase arrangement. In FIG. 13, (a) is an arrangement corresponding to the first embodiment, (b) is an arrangement corresponding to the second embodiment, and (c) is an arrangement corresponding to the third embodiment. Further, it is also applicable to 10P12S × n (20P24S, 30P36S ...) And 14P12S × n (28P24S, 42P36S ...) (n is a positive integer). Further, in FIGS. 5 to 8, various values are analyzed by the Y-connected motor, but the brushless motor according to the present invention may be a Δ-connected motor.

The present invention can be widely applied not only to motors for electric power steering devices but also to brushless motors equipped with two field windings, and can also be applied to motors for bi-wire systems such as steering and brakes. be.

1 Brushless motor 2 Stator 3 Rotor 4 Motor case 5 Teeth 5a to 5l (1) to (12) Teeth 6 Stator core 7 Coil 7AU U phase A coil 7BU U phase B coil 8 Slot 9 Rotor shaft 11 Rotor core 12 Magnet 13 Cover 21 Brushless motor 31 Brushless motor 41 Brushless motor 51 Brushless motor 52 Stator 53 Rotor 54 Magnet 55 Teeth 56 Coil 56AU U-phase A system coil 56BU U-phase B system coil A First system of field winding Second system of B field winding Gu U phase teeth group Gv V phase teeth group Gw W phase teeth group Vua U phase induced voltage synthesis vector (A system)
Vub U phase induced voltage synthesis vector (B system)

Claims (5)

It has a stator and a rotor arranged radially inside the stator.
The stator comprises 12 × n teeth and a multi-phase coil wound around the teeth in a concentrated winding.
The rotor includes 10 × n or 14 × n magnets.
The coil is a brushless motor formed by forming two field windings that are energized as separate systems (n is a positive integer).
The coils forming the same phase are grouped, and the coils are set at adjacent or overlapping positions in terms of electrical angle.
The teeth around which the coil at the position is wound are arranged on the stator at a mechanical angle corresponding to the electric angle.
A brushless motor characterized in that the coil is divided into the two systems and the field windings of the two systems are energized with a predetermined phase difference. In the brushless motor according to claim 1,
The stator has 12 teeth, the rotor has 10 or 14 magnets, and the coil is energized with a three-phase current.
The teeth are wound with the coils having the same phase in groups of four adjacent ones.
Two adjacent coils of the four teeth in the same phase belong to each system of the field winding.
A brushless motor characterized in that two systems of field windings are energized with a phase difference of 60 °. In the brushless motor according to claim 1,
The stator has 12 teeth, the rotor has 10 or 14 magnets, and the coil is energized with a three-phase current.
The coil is wound around the teeth so that the adjacent teeth are out of phase with each other.
When three adjacent teeth belonging to different phases are grouped into one group, the coils of the two adjacent teeth in the group are in one of the two field windings. The coil of the remaining one of the teeth in the group belongs to the other of the two systems.
A brushless motor characterized in that two systems of field windings are energized with a phase difference of 60 °. In the brushless motor according to claim 1,
The stator has 12 teeth, the rotor has 10 or 14 magnets, and the coil is energized with a three-phase current.
In the teeth, the coils having the same phase are wound around three adjacent groups as one group, and one of the teeth arranged between the adjacent groups has a phase different from that of the group on both sides. The coil is wound and
Two adjacent coils of the teeth in the group belong to one of the two fields of the field windings and are between the remaining one in the group and the group in another phase. The coil of one of the teeth arranged in the above belongs to the other system of the two systems.
A brushless motor characterized in that two systems of field windings are energized with a phase difference of 30 °. It has a stator and a rotor arranged radially inside the stator.
The stator comprises 12 × n teeth and a multi-phase coil wound around the teeth in a concentrated winding.
The rotor includes 10 × n or 14 × n magnets.
The coil is a control method for a brushless motor that forms two field windings that are energized as separate systems (n is a positive integer).
The coils forming the same phase are grouped, and the coils are set at adjacent or overlapping positions in terms of electrical angle.
The teeth around which the coil at the position is wound are arranged on the stator at a mechanical angle corresponding to the electric angle.
The coil is divided into the two systems,
A brushless motor control method characterized in that the field windings of the two systems are energized with a predetermined phase difference.

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