JP2020048313A - Reluctance motor - Google Patents

Abstract

To reduce torque ripples more than conventional techniques.SOLUTION: A reluctance motor comprises: a rotational shaft; a rotor mounted on the rotational shaft and having a plurality of projection poles; a stator provided with a plurality of slots; and a motor case for housing the rotor and the stator. Arrangement phases of the plurality of projection poles in a circumference direction of the rotor with respect to the plurality of slots are different in multiple stages in an axial direction of the rotational shaft.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reluctance motor.

  Patent Literature 1 below discloses a reluctance motor including a rotor having a plurality of salient poles. This reluctance motor is a type of motor in which the rotor is rotated by magnetic attraction acting between the salient poles and the slots of the stator. Since the rotor does not use permanent magnets or rotor windings, the structure is extremely simple. It is.

Japanese Patent Application Laid-Open No. 06-062540

  By the way, the reluctance motor has a disadvantage that the torque ripple is given by the attraction force, so that the torque ripple is relatively large. Therefore, in applications where torque ripple is a problem, there is a problem that a reluctance motor cannot be employed as a power source.

  The present invention has been made in view of the above-described circumstances, and has an object to reduce torque ripple as compared with the related art.

  In order to achieve the above object, according to the present invention, as a first solution of a reluctance motor, a revolving motor includes a rotating shaft, a rotor mounted on the rotating shaft and having a plurality of salient poles, and a plurality of slots. A stator, and a motor case accommodating the rotor and the stator, wherein the arrangement phases of the plurality of salient poles in the circumferential direction of the rotor with respect to the plurality of slots are different in multiple stages in the axial direction of the rotating shaft. Adopt means.

  In the present invention, as a second solving means according to the reluctance motor, in the first solving means, the rotor is provided as a plurality of individual rotors adjacent in the axial direction, and the plurality of rotors formed on the individual rotor are provided. The salient pole employs a means that the arrangement phases of the plurality of slots are different.

  In the present invention, as a third solution related to a reluctance motor, in the first solution, the stator is provided as a plurality of individual stators adjacent in the axial direction, and the plurality of stators provided in the individual stator are provided. The slot employs a means in which the arrangement phases of the plurality of salient poles are different.

  According to the present invention, as a fourth solution of the reluctance motor, in the above second or third solution, the means that the number of the individual rotors or the individual stators is two is adopted.

  According to the present invention, as a fifth solution of the reluctance motor, in any one of the first to fourth solutions, a drive circuit for supplying a drive current to the stator is provided inside the motor case. A means is adopted to cover a part.

  According to a sixth aspect of the present invention, as the sixth aspect of the reluctance motor, in the fifth aspect, the drive circuit is configured to, when increasing and reaching a predetermined value, hold the predetermined value for a predetermined time. A means of generating a current is employed.

 According to the present invention, it is possible to reduce the torque ripple as compared with the related art.

It is a perspective view showing the structure of the reluctance motor concerning one embodiment of the present invention. FIG. 2 is a circuit diagram illustrating a functional configuration of a motor drive device according to an embodiment of the present invention. 5 is a timing chart showing a motor drive waveform according to an embodiment of the present invention. It is a perspective view showing the structure of the reluctance motor concerning the modification of one embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The reluctance motor according to the present embodiment is a switch reluctance motor including a motor case 1, two individual stators 2A and 2B, a control board 3, a rotating shaft 4, and two individual rotors 5A and 5B as shown in FIG. is there. The two individual stators 2A, 2B constitute a stator as a whole, and the two individual rotors 5A, 5B constitute a rotor as a whole.

  The motor case 1 supports both ends of the rotating shaft 4 and accommodates the two individual stators 2A and 2B, the control board 3 and the two individual rotors 5A and 5B such that one or both ends of the rotating shaft 4 are exposed. Container. One of the two individual stators 2A, 2B has a stator core 2a and a stator winding 2b, and the other individual stator 2B has a stator core 2c and a stator winding 2d.

  The stator core 2a is a magnetic component in which six teeth 2a2 (polar teeth) are formed at a predetermined pitch inside a cylindrical yoke 2a1, and is formed of a dust core or a laminated steel plate. The stator winding 2b is a conductive wire member related to the teeth 2a2 in the form of concentrated winding. Each tooth 2a2 around which the stator winding 2b is wound constitutes a slot together with the stator winding 2b. That is, one individual stator 2A has “6” slots as shown in FIG.

  On the other hand, the stator core 2c is a magnetic component in which six teeth 2c2 (pole teeth) are formed at a predetermined pitch inside a cylindrical yoke 2c1, and is formed of a dust core or a laminated steel plate. The stator winding 2d is a conductive wire member related to the teeth 2c2 in a concentrated winding form. Each tooth 2c2 around which the stator winding 2d is wound forms a slot together with the stator winding 2d. That is, the number of slots of the other individual stator 2B is “6” as in the case of the one individual stator 2A.

  Here, FIG. 1 shows a state in which, among the six teeth 2a2, 2c2 formed on each stator core 2a, 2c2, only three adjacent stator windings 2b, 2d are provided with stator windings 2b, 2d. It is expedient. That is, the stator winding 2b is wound around all (six) teeth 2a2, 2c2 formed on the stator core 2a, respectively, and the stator winding 2d is formed on all (six) the stator core 2c. Are wound around the teeth 2a2 and 2c2, respectively.

  Of the stator windings 2b wound around the teeth 2a2 and 2c2 of the stator core 2a, the stator windings 2b of a pair of slots opposed to each other with the central axis of the stator core 2a interposed therebetween are driven in the same phase by a drive circuit described later. A drive current is supplied. That is, the two individual stators 2A and 2B have three pairs of slots facing each other across the central axis of the stator core 2a, and the stator windings 2b of the respective slots have electrical angles of 120 ° with each other. Different three-phase drive currents (U-phase drive current, V-phase drive current, and W-phase drive current) are supplied from the drive circuit.

  As shown in FIG. 1, the two individual stators 2A and 2B are adjacent to each other in the axial direction of the rotating shaft 4 and have respective slots (that is, each of the slots around the central axis of the stator cores 2a and 2c). The teeth 2a2, 2c2) are accommodated in the motor case 1 so that the arrangement phases are the same. That is, in the direction from one end of the center axis of the stator cores 2a, 2c to the other end, that is, in the axial direction of the rotary shaft 4, each slot (each tooth 2a2, 2c2) of the individual stator 2A and each slot (each tooth 2a2) of the individual stator 2B. , 2c2).

  The control board 3 is mounted in the motor case 1 so as to cover a part of the two individual stators 2A and 2B. The control board 3 has a drive circuit for supplying three-phase drive currents (U-phase drive current, V-phase drive current, and W-phase drive current) to each stator winding 2b mounted on a printed wiring board. .

  The rotating shaft 4 is a long cylindrical metal member. The two individual rotors 5 </ b> A and 5 </ b> B are magnetic members mounted on the rotating shaft 4, and are provided so as to be adjacent to each other in the axial direction of the rotating shaft 4. Of these two individual rotors 5A, 5B, one salient pole 5a is provided on one individual rotor 5A, and four salient poles 5b are provided on the other individual rotor 5B. The salient poles 5a, 5b are provided at a pitch angle of 90 ° around the axis of the rotating shaft 4 in a direction orthogonal to the axial direction of the rotating shaft 4 as shown in the figure.

  Here, as shown in FIG. 1B, the salient poles 5a of the one individual rotor 5A and the salient poles 5b of the other individual rotor 5B have an arrangement phase around the axis of the rotating shaft 4 as an angle. a °. That is, the arrangement phases of the plurality of salient poles 5a, 5b in the circumferential direction of the two individual rotors 5A, 5B with respect to the plurality of slots differ in two stages (multistage) in the axial direction of the rotating shaft 4. This angle a ° is set to, for example, 15 °. Note that the phase difference between the arrangement position of the four salient poles 5a and the arrangement position of the four salient poles 5b in the two individual rotors 5A and 5B, that is, the angle a ° is appropriately set within a range not exceeding 45 °, for example. You.

  Subsequently, a motor drive device for controlling and driving the reluctance motor according to the present embodiment will be described with reference to FIG. This motor drive device includes a battery 6, a battery control device 7, four smoothing capacitors 8A to 8D, drive transistors 9A and 9B, diodes 10A and 10B, and a control circuit 11.

  The battery 6 is an assembled battery in which many battery cells are connected in series, and is, for example, a lithium ion battery. The battery 6 outputs an output voltage (battery voltage) to the control board 3. The battery control device 7 is a control device that controls the operation state of such a battery 6. The battery control device 7 detects, for example, the voltage (cell voltage) of each battery cell, and controls charging and discharging of each battery cell based on the cell voltage.

  The four smoothing capacitors 8A to 8D are provided on the input side of the control board 3, and smooth the battery voltage input from the battery 6. Of the three smoothing capacitors 8A to 8D, the smoothing capacitor 8A is an electrolytic capacitor as shown, one end of which is connected to the plus terminal of the battery 6, and the other end of which is connected to the minus terminal of the battery 6. The smoothing capacitor 8B is a film capacitor, one end of which is connected to the plus terminal of the battery 6, and the other end of which is connected to one end of the smoothing capacitor 8C and one end of the smoothing capacitor 8D.

  The smoothing capacitor 8C is also a film capacitor. One end is connected to the other end of the smoothing capacitor 8B and one end of the smoothing capacitor 8D, and the other end is connected to the minus terminal of the battery 6. The smoothing capacitor 8D is also a film capacitor, and one end is connected to the other end of the smoothing capacitor 8B and one end of the smoothing capacitor 8C, and the other end is grounded.

  The driving transistors 9A and 9B are switching transistors whose operations are controlled by the control circuit 11. Of these drive transistors 9A and 9B, one drive transistor 9A has an output terminal connected to the stator winding 2b of one individual stator 2A as shown in the figure, and the other drive transistor 9B has an output terminal connected to the other individual stator 2A. 2B is connected to the stator winding 2d.

  Here, in one individual stator 2A, three stator windings 2b are individually provided corresponding to three phases (U phase, V phase and W phase). In the other individual stator 2B, three stator windings 2d are provided individually corresponding to three phases (U-phase, V-phase and W-phase). In FIG. 2, one driving transistor 9A and the other driving transistor 9B are each drawn for convenience, but one driving transistor 9A and the other driving transistor 9B are connected to three stator windings 2b and 2d. Three are provided correspondingly.

  The diodes 10A and 10B are provided corresponding to the three stator windings 2b and 2d thus provided. The diodes 10A and 10B are connected in parallel to the respective stator windings 2b and 2d as shown in the figure, and absorb surge voltages generated in the respective stator windings 2b and 2d. The control circuit 11 controls the supply of the drive current to each of the stator windings 2b and 2d by turning on / off the drive transistors 9A and 9B.

  Here, among the components of such a motor drive device, the drive transistors 9A and 9B, the diodes 10A and 10B, and the control circuit 11 are mounted on the control board 3 housed in the motor case 1 and described above. It constitutes a drive circuit. Further, the four smoothing capacitors 8A to 8D are integrally mounted outside the motor case 1.

  Next, the operation of the reluctance motor according to the present embodiment will be described in detail with reference to FIG. In FIG. 3, one of two adjacent slots among the six slots of the reluctance motor is called a first slot, and the other is called a second slot.

  The reluctance motor according to the present embodiment is a switch reluctance motor in which the number of slots in each of the individual stators 2A and 2B is “6” and the number of poles in each of the individual rotors 5A and 5B is “4”. The apparatus supplies a drive current to each of the stator windings 2b and 2d every 30 degrees at a rotation angle of each of the individual rotors 5A and 5B as shown in the figure. That is, the control circuit 11 changes the drive transistors 9A and 9B to the ON state every 30 degrees based on the rotation angles of the individual rotors 5A and 5B detected by the rotation sensors (not shown), so that the control circuits 11 Then, a drive current is supplied to each of the stator windings 2b and 2d.

  Here, in the reluctance motor according to the present embodiment, the arrangement phase of the salient poles 5b of the other individual rotor 5B is a rotation angle of a ° (for example, 15 °) with respect to the arrangement phase of the salient poles 5a of the one individual rotor 5A. As shown in the lower two waveforms of FIG. 3, the drive current of the first slot (first energization) and the drive current of the second slot (second energization) 15 °).

  When the first current is a drive current supplied to the stator winding 2b of one individual stator 2A and the second current is a drive current supplied to the stator winding 2d of the other individual stator 2B, one individual current is used. The attraction force generated between the first slot and the salient pole 5a of the individual rotor 5A based on the magnetic force generated by the stator winding 2b of the stator 2A causes the individual rotor 5A shown in the uppermost waveform in FIG. (First torque) is generated, and the attracting force generated between the second slot and the salient pole 5c of the individual rotor 5B based on the magnetic force generated by the stator winding 2d of the other individual stator 2B, as shown in FIG. A rotating torque (second torque) is generated in the individual rotor 5B shown in the second waveform from the top.

  That is, the waveforms of the first torque and the second torque are increased / decreased waveforms which gradually increase and then gradually decrease as shown in the figure, but have a phase difference of a ° (for example, 15 °) with each other. Each of the individual rotor 5A and the other individual rotor 5B is fixed to the rotating shaft 4. The broken line of the torque waveform in FIG. 3A is a torque waveform when a constant current is applied, and the solid line is a waveform when the first and second energizations are applied. Torque) is the sum of the first torque and the second torque.

  According to this embodiment, at least two individual rotors 5A and 5B in which the arrangement phases of the two individual stators 2A and 2B having the same configuration and the salient poles 5a and 5b are different by an angle a ° (for example, 15 °) are provided. Therefore, a phase difference occurs between the first torque and the second torque. Therefore, according to the present embodiment, the torque ripple of the motor torque can be reduced as compared with the related art by the first torque and the second torque having a phase difference.

  Further, according to the present embodiment, a drive circuit for supplying a drive current to the two individual stators 2A, 2B is mounted inside the motor case 1 so as to cover a part of the two individual stators 2A, 2B. . Therefore, according to the present embodiment, it is possible to suppress variations in the characteristics of the three-phase (U-phase, V-phase, and W-phase) stator windings 2b, 2d, and thus to suppress a difference in rotational torque between phases. It is possible.

Note that the present invention is not limited to the above embodiment, and for example, the following modified examples can be considered.
(1) In the above embodiment, the configuration including the two individual stators 2A and 2B and the two individual rotors 5A and 5B has been described, but the present invention is not limited to this. As a modified example of the present embodiment, for example, a configuration as shown in FIG. 4, that is, a configuration including two individual stators 2A and 2C and one rotor 5C can be considered. Of the two individual stators 2A and 2C, the individual stator 2C includes a stator core 2e and a stator winding (not shown).

  The stator core 2e is a magnetic component in which six teeth 2e2 (polar teeth) are formed at a predetermined pitch inside a cylindrical yoke 2e1 similarly to the individual stator 2A described above, and is formed by a dust core or a laminated steel plate. Have been. That is, the individual stator 2C includes six slots. In such an individual stator 2C, the arrangement phase of the six teeth 2e2 around the rotation axis 4, that is, the slots, is shifted from the arrangement phase of the teeth 2a2 (that is, the slots) of the individual stator 2A by an angle a ° (for example, 15 °). I have.

  On the other hand, one rotor 5C has four salient poles 5c, and these salient poles 5c are elongated in the axial direction of the rotating shaft 4 so as to face each slot of the individual stator 2A and each slot of the individual stator 2C. Is formed. In the reluctance motor according to such a modification, a phase difference occurs between the first torque generated in the rotor 5C with the individual stator 2A and the third torque generated in the rotor 5C with the individual stator 2C. Therefore, it is possible to suppress the torque ripple of the motor torque more than before.

  That is, in the reluctance motor according to the above-described embodiment, the two individual stators 2A and 2B having the same slot arrangement phase and the two individual rotors 5A and 5B differ in the arrangement phase of the pole teeth by an angle a ° (for example, 15 °). Are combined to generate the first torque and the second torque having different phase relationships. However, in the reluctance motor according to the present modification, the arrangement phases of the slots differ by an angle a ° (for example, 15 °). By combining the two individual stators 2A, 2B and the two individual rotors 5A, 5B having the same arrangement phase of the pole teeth, the first torque and the third torque having different phase relationships are generated.

(2) In the above embodiment, the torque ripple of the motor torque is suppressed by combining the first torque and the second torque having different phases or the first torque and the third torque having different phases, but the present invention is not limited to this. . That is, the number of torques to be combined, that is, the number of individual stators or individual rotors is not limited to two, and may be three or more.

(3) In the above embodiment, the triangular drive current is supplied to the stator windings 2b, 2d and the like as shown in FIG. 3, but the present invention is not limited to this. As shown in the upper waveform of FIG. 3B, for example, during normal rotation, a triangular drive current is supplied to the stator windings 2b, 2d, etc., while the rotation speed is lower than a predetermined threshold value. At times, a drive current having a waveform as shown in the lower waveform of FIG. 3B may be supplied to the stator windings 2b, 2d and the like.

  In other words, when the rotation speed is low, when the drive circuit increases and reaches a predetermined value, the drive circuit holds the predetermined value for a certain period of time, generates a drive current having a waveform falling after the hold, and supplies the drive current to the reluctance motor. According to such a low-rotation drive current, since the current has a current flat portion, it is possible to suppress the torque ripple of the motor torque more than a triangular-wave drive current having no current flat portion. It should be noted that the drive current having the current flat portion is more effective at the time of low rotation, but may be used at the time of normal rotation.

DESCRIPTION OF SYMBOLS 1 Motor case 2A, 2B Individual stator 2a, 2c Stator core 2b, 2d Stator winding 2a1, 2c1 Yoke 2a2, 2c2 Teeth 3 Control board 4 Rotating shaft 5A, 5B Individual rotor 6 Battery 7 Battery control device 8A-8D Smoothing capacitor 9A 9B Driving transistor 10A, 10B Diode 11 Control circuit

Claims (6)

A rotation axis,
A rotor mounted on the rotating shaft and formed with a plurality of salient poles,
A stator having a plurality of slots;
A motor case that houses the rotor and the stator,
A reluctance motor, wherein the arrangement phases of the plurality of salient poles with respect to the plurality of slots in the circumferential direction of the rotor differ in multiple stages in the axial direction of the rotating shaft. The rotor is provided as a plurality of individual rotors adjacent in the axial direction,
The reluctance motor according to claim 1, wherein the plurality of salient poles formed on the individual rotor have different arrangement phases with respect to the plurality of slots. The stator is provided as a plurality of individual stators adjacent in the axial direction,
2. The reluctance motor according to claim 1, wherein the plurality of slots provided in the individual stator have different arrangement phases with respect to the plurality of salient poles. 3.   4. The reluctance motor according to claim 2, wherein the number of the individual rotors or the individual stators is two.   The reluctance according to any one of claims 1 to 4, wherein a drive circuit that supplies a drive current to the stator is mounted inside the motor case so as to cover a part of the stator. motor.   The reluctance motor according to claim 5, wherein when the drive circuit increases and reaches a predetermined value, the drive circuit generates the drive current that holds the predetermined value for a predetermined time.

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