JP4923633B2 - Switched reluctance motor - Google Patents

Description

  The present invention relates to a switched reluctance motor (hereinafter also referred to as an SR motor) configured to improve an average torque per rotation of a rotor.

2. Description of the Related Art Conventionally, a two-phase driving SR motor is known as an example of an SR motor including a rotor and a stator described above (see Non-Patent Document 1, pages 25 to 26). In such a two-phase driving SR motor, a torque can be generated simultaneously on all salient poles of the rotor, and a three-phase driving SR motor that simultaneously generates torque on only half of the salient poles of the rotor. In comparison, the average torque per rotation of the rotor is large.
"Switched Reluctance Motors and their Control"(TJEMILLER; MAGNA PHYSICS PUBLISHING OXFORD SCIENCE PUBLICATIONS)

  However, in the conventional two-phase driving SR motor, there is no change with respect to the rotation direction of the inductance in the vicinity of the angle at which the salient poles of the rotor and the stator are completely opposed, or in the vicinity of the completely non-opposed rotor angle. Therefore, there is a problem that torque cannot be generated. Examples of the two-phase driving SR motor that solves this problem and can generate torque at all rotor angles include a stepped gap SR motor and a cam SR motor (Non-Patent Document 1, 27-28). Page). In these SR motors, a step is provided in the radial length of the salient poles of the rotor or the shape is changed in a tapered shape. As a result, a change in the inductance rotation direction occurs, and torque can be generated at all rotor angles. However, even in this method, the rotation direction in which the inductance always changes is limited to one direction, and there is a problem that the reverse rotation is difficult.

  An object of the present invention is a motor that eliminates the above-described problems, eliminates the state where torque cannot be generated, and can be reversely rotated, and is configured to improve the average torque per one rotation of the rotor. It is intended to provide a reluctance motor.

  The switched reluctance motor of the present invention is a switched reluctance motor composed of a rotor and a stator, and is a first switched reluctance motor unit that is driven with three or more phases, And a second switched reluctance motor unit driven in two phases.

  According to the present invention, the first switched reluctance motor unit that is driven with three or more phases and the second switched reluctance motor unit that is driven with two phases are used. Therefore, it is possible to obtain a switched reluctance motor which eliminates the state where the motor cannot be generated and is capable of reverse rotation and is configured to improve the average torque per one rotation of the rotor.

  As a preferred example of the switched reluctance motor of the present invention, a stator region corresponding to a circumferential angle including at least one salient pole of the first switched reluctance motor unit. Shows the same shape as the stator of a switched reluctance motor driven with three or more phases, and in the region of the stator corresponding to the remaining angle in the circumferential direction, it is driven with two phases. A stator structure having the same shape as the stator of a switched reluctance motor may be provided. With this configuration, the number of rotor salient poles that can generate torque at the same time is increased as compared with the conventional three-phase driving SR motor, and thus the average torque can be increased. Further, there is no rotor angle at which torque is not generated, which was a problem with conventional two-phase drive SR motors, and torque can be generated in any direction.

  As a preferred example of the switched reluctance motor according to the present invention, a region corresponding to the circumferential angle of the stator where the salient poles of the second switched reluctance motor unit are arranged is the first region. This may be larger than the area corresponding to the circumferential angle of the stator where the salient poles of the switched reluctance motor section are arranged. By configuring in this way, the range of the stator that is driven in two phases increases, and at the same time, the number of rotor salient poles that can generate torque increases, so that the average torque can be increased in addition to the above-described effects. .

  Further, as a preferred example of the switched reluctance motor of the present invention, an even number of salient poles of the first switched reluctance motor unit and the second switched reluctance motor unit are provided per phase. May be arranged point-symmetrically around the axis of the rotor. With this configuration, the radial force generated in the rotor is canceled out, and the radial force imbalance can be suppressed.

  Furthermore, as a preferred example of the switched reluctance motor of the present invention, the first switched reluctance motor unit has a switched reluctance motor in which the stator is 12 poles and the rotor is 8 poles and is driven in three phases. It may be a part of a motor, and the second switched reluctance motor part may be a part of a switched reluctance motor that is driven in two phases with a stator having 12 poles and a rotor having 8 poles. By configuring in this way, the various effects described above can be realized.

  Further, as a preferred example of the switched reluctance motor of the present invention, the first switched reluctance motor unit has a switched reluctance motor that is three-phase driven with a stator having 18 poles and a rotor having 12 poles. The second switched reluctance motor unit may be a part of a switched reluctance motor that is driven in two phases with a stator having 24 poles and a rotor having 12 poles. With this configuration, the various effects described above can be realized, and more than the above-described configuration, the torque ripple can be expected to be reduced.

Embodiments of the present invention will be described below in detail with reference to the drawings.
1 to 4 are diagrams for explaining one embodiment of the switched reluctance motor of the present invention. First, the configuration will be described. In the configuration shown in FIG. 1, the SR motor 1 includes a stator 2 and a rotor 3. In this example, the stator 2 has 14 poles and the rotor 3 has 8 poles. The SR motor is driven by five phases. In the region 2a above the dotted line in the figure, the stator 2 has the same shape as an SR motor that has three poles and the stator 2 has 12 poles and the rotor 3 has 8 poles. In the region 2b, the stator 2 has 16 poles and the rotor 3 has 8 poles, and has the same shape as the SR motor driven in two phases.

  In the example shown in FIG. 1, the width of the salient pole in the 8-pole rotor 3 is 15 ° in mechanical angle. The width of all salient poles of the stator 2 is also set to a mechanical angle of 15 °. In the example shown in FIG. 1, 4a is an A-phase winding for two-phase driving, 4b is a B-phase winding for two-phase driving, 4u is a U-phase winding for three-phase driving, and 4v is three-phase driving. V-phase windings 4w are W-phase windings for three-phase driving.

  Next, the driving circuit for the SR motor in this embodiment will be described with reference to FIG. In the drive circuit shown in FIG. 2, 10a to 10j are switching elements, 11a to 11j are diodes, 12u, 12v, 12w, 12a and 12b are winding current sensors, and 13 is a DC power source. As shown in FIG. 2, each phase winding 4u, 4v, 4w, 4a, 4b is connected to the DC power supply 13 by a general half bridge circuit and is driven in five phases.

  Next, the operation in this embodiment will be described. FIG. 3 shows the energization timing of the switching elements 10a to 10j. In the timing chart shown in FIG. 3, a high level means on and a low level means off. The horizontal axis represents the mechanical angle of the rotor 3, and the position shown in FIG. 1 is set to a mechanical angle of 0 °, and the mechanical angle increases counterclockwise. In each phase, energization is started from an angle at which the salient poles of the rotor 3 begin to face the salient poles of the stator 2, and energization is terminated at an angle completely opposed.

  Next, the effect in a present Example is demonstrated. FIG. 4 shows a schematic diagram of each phase torque when a constant current value I [A] is applied at the timing as shown in FIG. A conventional SR motor having 12 poles and a rotor having 8 poles is driven in three phases, and the SR motor of the same size as the present embodiment starts from the angle at which the rotor salient poles start to face the stator salient poles. The torque generated in one salient pole is assumed to be 1.

  In the present embodiment, as shown in FIG. 4, the V phase generates torque at two salient poles of the rotor 3 in a mechanical angle range of 15 °, so the average torque per one mechanical angle rotation is 2 ÷ 45. X15 = 0.67. Similarly, the average torque of the W phase is 0.67, and the energization timings of the A phase and the U phase are the same, so the total torque is 6 salient poles, the average torque is 2.0, the B phase is 4 salient poles, and the average torque is 1. 33, and the average torque of the entire motor is 4.67. On the other hand, the conventional SR motor, which has a salient pole stator of 12 poles and a rotor of 8 poles and is driven in three phases, generates torque at 4 salient poles, so the average torque is 4.0. Then, it is possible to increase the torque by about 17% with the same physique.

  In the above-described embodiment, each switching element is kept on for a fixed rotor angle. However, in order to energize a constant current value, it is of course possible to specify PWM control or hysteresis comparator control. Is possible. Further, the energization start angle and the energization end angle are not limited to those in FIG. 3, and the timing may be changed according to the rotation speed and the DC voltage.

  FIG. 5 and FIG. 6 are diagrams for explaining other examples of the switched reluctance motor of the present invention. First, the configuration will be described. In the configuration shown in FIG. 5, the SR motor 21 includes a stator 22 and a rotor 23. In this example, the stator 22 has 22 poles and the rotor 23 has 12 poles. The SR motor is driven by five phases. In the region 22a of 60 ° counterclockwise from the position of the mechanical angle 0 ° in FIG. 5 and the region 22c of 240 ° from the position of 180 °, the stator 22 has 18 poles and the rotor 23. Has the same shape as an SR motor that drives three phases with 12 poles. In the region 22b from 60 ° to 180 ° and the region 22d from 240 ° to 360 °, the stator 22 is 24 poles and the rotor 23 Has the same shape as an SR motor driven by two poles with 12 poles.

  In the example shown in FIG. 5, the width of the salient pole in the 12-pole rotor 23 is 10 ° in mechanical angle. Note that the width of all salient poles of the stator 22 is also set to a mechanical angle of 10 °. In the example shown in FIG. 5, 24a is an A-phase winding for two-phase driving, 24b is a B-phase winding for two-phase driving, 24u is a U-phase winding for three-phase driving, and 24v is three-phase driving. The V-phase winding 24w is a W-phase winding for three-phase driving.

  In this embodiment, the drive circuit and its energization timing are the same as those in the embodiment described with reference to FIGS.

  Next, the effect in a present Example is demonstrated. FIG. 6 shows the torque calculated by the same procedure as in FIG. 4 in the above-described embodiment. The conventional SR motor, which is three-phase driven with 18 poles of the salient pole stator and 12 poles of the rotor, is completely the same as the present embodiment from the angle at which the salient pole of the rotor starts to face the salient pole of the stator. The torque generated at one salient pole of the rotor when the current value I [A] is applied to the winding of the phase during the angle opposite to.

  In FIG. 6, the V phase and the W phase each have 2 salient poles with an average torque of 0.67, the A phase has 10 salient poles, the average torque is 3.33, the B phase has 8 salient poles, and the average torque is 2.67. The average torque of the entire motor is 7.34. On the other hand, in the conventional SR motor that is driven in three phases by the salient pole stator 18 poles and the rotor 12 poles, the torque is always generated at the 6 salient poles, so the average torque is 6.0, and this embodiment is the same. It is possible to increase the torque by about 22% in the physique.

  Furthermore, in this embodiment, each phase is arranged point-symmetrically with respect to the rotor shaft center, so that the radial force generated in the rotor is canceled and the radial force imbalance is suppressed. it can. Further, the regions 22b and 22d for two-phase driving are increased from the regions 22a and 22c for three-phase driving, and the average torque can be increased.

  In any of the above-described embodiments, the rotor salient pole and the stator salient pole have the same width, but need not necessarily be the same.

  According to the switched reluctance motor of the present invention, a first switched reluctance motor unit that is driven with three or more phases, and a second switched reluctance motor unit that is driven with two phases, Therefore, it is possible to eliminate the state where torque cannot be generated and to perform reverse rotation, and to increase the average torque per one rotation of the rotor. Therefore, the SR motor can be suitably used for applications such as improving the average torque per rotation of the rotor.

It is a figure for demonstrating one Example of the switched reluctance motor of this invention. It is a figure which shows an example of the SR motor drive circuit in the Example shown in FIG. It is a figure which shows an example of the energization timing of the SR motor drive circuit in the Example shown in FIG. It is a figure which shows the torque outline of the SR motor in the Example shown in FIG. It is a figure for demonstrating the other Example of the switched reluctance motor of this invention. It is a figure which shows the torque outline of the SR motor in the Example shown in FIG.

Explanation of symbols

1, 21 Switched reluctance motor 2, 22 Stator 3, 23 Rotor 4a, 24a A phase winding 4b, 24b B phase winding 4u, 24u U phase winding 4v, 24v V phase winding 4w, 24w W-phase winding 10a to 10j Switching element 11a to 11j Diode 12a, 12b, 12u, 12v, 12w Winding current sensor 13 DC power supply

Claims (6)

  A switched reluctance motor comprising a rotor and a stator, wherein the first switched reluctance motor unit is driven by three or more phases, and the second switched reluctance motor unit is driven by two phases. A switched reluctance motor characterized by comprising a reluctance motor unit.   In a stator region corresponding to an angle in the circumferential direction including at least one salient pole of the first switched reluctance motor unit, the switched reluctance motor that is driven with the number of phases of three or more phases. Stator structure showing the same shape as the motor stator and the same shape as the stator of a switched reluctance motor driven in two phases in the stator region corresponding to the remaining circumferential angle The switched reluctance motor according to claim 1, wherein   The region corresponding to the circumferential angle of the stator where the salient pole of the second switched reluctance motor unit is arranged is the stator where the salient pole of the first switched reluctance motor unit is arranged The switched reluctance motor according to claim 1, wherein the switched reluctance motor is larger than a region corresponding to an angle in a circumferential direction.   Equipped with an even number of salient poles per phase for the first switched reluctance motor section and the second switched reluctance motor section, and each salient pole of the same phase is point-symmetric about the rotor axis The switched reluctance motor according to claim 1, wherein the switched reluctance motor is arranged.   The first switched reluctance motor unit is a part of a switched reluctance motor that is driven in three phases with a stator of 12 poles and a rotor of 8 poles, and the second switched reluctance motor unit is The switched reluctance motor according to any one of claims 1 to 4, wherein the switched reluctance motor is a part of a switched reluctance motor that is driven in two phases with a stator of 12 poles and a rotor of 8 poles. motor. The first switched reluctance motor unit is a part of a switched reluctance motor that is three-phase driven with a stator of 18 poles and a rotor of 12 poles. The second switched reluctance motor unit is The switched reluctance motor according to any one of claims 1 to 4 , wherein the switched reluctance motor is a part of a switched reluctance motor that is driven in two phases with a stator of 24 poles and a rotor of 12 poles. motor.

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