JPH07250458A - Reluctance motor - Google Patents

Abstract

PURPOSE:To suppress synchronization step-out in a reluctance motor and to decrease torque ripples. CONSTITUTION:A rotor 10 having the hollow cylindrical structure, wherein a plurality of magnetic plates having salient poles are laminated in a shape that inductance change forms the sine-wave pattern in the rotating direction, is provided. An external stator 4 is arranged at the outer surface side of the rotor 10, and an inner stator 5 is arranged at the inner surface side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous electric motor used for positioning such as a feed shaft of a machine tool for a servo, and more particularly to a reluctance electric motor.

[0002]

2. Description of the Related Art FIG. 6 is a cross sectional view showing a structure of a stator and a rotor of a conventionally known reluctance type electric motor.
A plurality of slits are radially provided on the inner peripheral surface of the stator 62 having a structure in which a plurality of magnetic material plates are laminated,
The rotor 61 is inserted inside the stator 62. A plurality of (six in the figure) salient poles are radially provided on the outer peripheral surface of the rotor 61, and a shaft 63 is provided at the center of rotation of the rotor 61.
Has been penetrated. Both ends of the shaft 63 are rotatably supported by bearings or the like. The rotor 61 is configured to rotate relative to the stator 62 based on a signal from a detector or the like (not shown) provided at the shaft end.

[0003]

In the above-mentioned conventional reluctance type motor, as the load increases, the magnetic pole axis of the rotor is rotated from the rotary magnetic pole axis of the stator by an angle δ in the reverse rotation direction.
It only shifts and reluctance torque is generated. This angle δ
Is called the internal phase difference angle (or load angle). In the case of a reluctance type motor with salient pole structure, when δ> π / 4, the torque decreases and the rotor stops at the synchronous speed and stops. A phenomenon called step out occurs. Therefore, in the case of overload, there is a problem that step-out easily occurs and control may be lost. Further, since the rotor of the reluctance type motor has a salient pole structure, the magnetic energy stored in the gap varies greatly depending on the relative position between the salient poles of the rotor and the stator having the slot, that is, the gap permeance is large. Since it has pulsation, it has a drawback that it has a large torque ripple and is not suitable for an electric motor for servo applications. The present invention has been made under the circumstances described above, and an object of the present invention is to provide a reluctance type electric motor capable of preventing step-out and reducing torque ripple.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a reluctance type electric motor, and the above object of the present invention is to provide a plurality of sheets having salient poles in such a manner that the change in inductance becomes sinusoidal in the rotational direction. It is achieved by including a rotor having a hollow cylindrical structure in which magnetic material plates of (1) are laminated in the rotation axis direction. Further, it is achieved by including a first stator arranged on the outer peripheral surface side of the rotor and a second stator arranged on the inner peripheral surface side of the rotor. Further, one stator of the first stator or the second stator is provided with a computing means for computing a field current command and an armature current command, and the other stator is provided with a rotor before the rotor. Control means is provided which refers to the detected position and the detected speed and performs current phase control based on the output from the computing means, and controls the current sent to the winding of the one stator by the output from the computing means. However, this is achieved by controlling the current sent to the winding of the other stator by the output from the control means.

[0005]

In the present invention, the stator has an outer stator and an inner stator such that a cylindrical rotor whose inductance changes sinusoidally on the inner peripheral surface and the outer peripheral surface with respect to the rotation axis is sandwiched between the outer stator and the inner stator. It is divided into two systems. The motor winding of one stator outputs a current command that is a phase operation of the current command of the other stator according to the current command map in the memory based on the rotor position and speed, so it is possible to prevent step-out. You can
In addition, a stable control can be performed by reducing the ripple of the output torque waveform together with the special structure of the rotor. further,
By dividing the stator into two systems, the winding diameter can be increased to allow a large current to flow, and since the number of windings can be divided into each, heat generation can be suppressed and rotation efficiency can be improved. You can

[0006]

1 is a cross-sectional structural view showing an example of a reluctance type electric motor of the present invention in correspondence with FIG. This is a structure in which a plurality of magnetic material plates each having a salient pole in a shape in which the inductance change has a sinusoidal shape in the rotation direction when viewed from the stator winding are laminated in the rotation axis direction. Magnetic pole structure 1
Is a cylindrical rotor 10 made of resin 2 which serves to fix and protect the magnetic pole structure 1 and at the same time prevent wind loss during rotation.
Is molded as. An internal stator 5 having a structure in which a plurality of magnetic material plates are laminated inside the rotor 10 in which a rotor 10 is inserted with a gap inside an external stator 4 similar to the stator 63 shown in FIG. Are inserted with a gap.
A plurality of slots are radially provided on the outer peripheral surface of the inner stator 5, and a shaft 6 is inserted in the center of the inner stator 5 with a gap. The magnetic pole structure 1 includes stators 4 and 5
It becomes a part that constitutes the magnetic pole by controlling the current from the. This magnetic pole forming body 1 is provided with a hole through which the shaft body 3 can pass, and the shaft body 3 focuses the magnetic material plates constituting the magnetic pole forming body 1 and simultaneously shows the rotor 10 forming body in FIG. Disk 11
Has the role of fixing to.

FIG. 2 is a partial vertical sectional structural view of the reluctance type electric motor of the present invention, which is expressed in a cut model. The shaft 6 is rotatably supported by the bearings 7 on the flanges 20 and 21. Rotor 10 (magnetic pole structure 1 and resin 2)
Is fixed to the disks 8 and 11 by the shaft body 3, and the disk 1
Since 1 is fixed to the shaft 6, the rotor 10 can rotate with the shaft 6. The disks 8 and 11 also serve as balancer weights. The windings 23 and 24 are housed in the slots of the outer stator 4 and the inner stator 5, respectively. Figure 3
FIG. 3 is a perspective view showing details of a rotor. Although not particularly shown in FIGS. 1 and 2, the cylindrical member 3 made of a non-magnetic material for protection is used.
1, 32 may be provided on the inner peripheral surface and the outer peripheral surface of the rotor 10, whereby the strength of the rotor 10 can be increased.

FIG. 4 is a diagram showing a change in inductance depending on the rotation angle of the rotor. A waveform 41 shows a change in the inductance of the conventional reluctance motor rotor shown in FIG. 6, and a waveform 42 shows a change in the inductance of the reluctance motor rotor according to the present invention. Change in magnetic energy stored in the gap at the relative position of the rotor and stator (or pulsation of gap permeance)
Causes torque ripple, but in the rotor shape of the conventional reluctance type motor, the inductance change is steep as shown by the waveform 41, so that a large torque ripple appears in the output torque. Therefore, when a sine wave is used as the control current, the change in the relative magnetic energy at the synchronous speed is reduced, so that the rotor of the reluctance motor of the present invention has a gradual change in the inductance in the rotating direction as shown by the waveform 42. It is shaped like this.

FIG. 5 is a block diagram showing an example of a control device of the reluctance type electric motor of the present invention. The position of the salient pole of the rotor 10 is detected by the detector 71, and its detection signal D
S is input to the rotor position detection circuit 72 and the speed detection circuit 73. The rotor position detection circuit 72 outputs the rotor position detection signal SP to the field current command unit 81 and the armature current command unit 82, and the speed detection circuit 73 outputs the speed detection signal SV to the armature current command unit 82. It is output to the subtractor 51. The speed command signal SVC is input to the subtracter 51, the speed detection signal SV is subtracted, and the speed controller (PID control) 52 inputs the field current command unit 81 as a torque signal together with the rotor position signal SP. The U-phase field current command signal SImu and the V-phase field current command signal SImv from the field current command unit 81, and the U-phase armature current command signal SIau and the V-phase field current command signal from the armature current command unit 82. SIav is output and input to the current command calculation unit 83. Then, after the respective vector operations are performed, the U-phase current command signal SIu and the V-phase current command signal SIv are output to the current control circuit 53 and the current phase control unit 57, and the current control circuit 5
External winding 2 after three-phase current conversion and power control in 3
4 is output. The rotor position detection signal SP and the speed detection signal SV are input to the current phase control unit 57, and the current command signals SIu and SIv are phase-controlled according to the current command map stored in the memory 58 and SIu.
It is output to the current control circuit 54 as ", SIv", and is output to the internal winding 23 after three-phase current conversion and power control. The current command in the memory 58 is the current rotor salient pole position and speed, and SIu commanded to the external winding.
And SIv, the maximum torque is mapped according to the relationship between the field and armature current and the rotor salient pole position.

The present invention is not limited to the embodiments of the present invention shown in FIGS. 1 to 5, and the following modifications can be made without departing from the spirit of the invention. Good. (1) In the rotor shape of the reluctance type electric motor of the present invention, the poles of the outer stator and the inner stator are arranged so as to show the same pole, but it is not always necessary to show the same pole, and either one of them is not necessary. The stator may be skewed. (2) Although a six-pole rotor is used in the description of the embodiment, a multi-pole type or a linear type may be used. (3) The ratio of the number of teeth of the external stator to the internal stator is 2: 1.
But not limited to 1: 1, 3: 1, or 3:
The configuration may be n: m (n ≧ m, which is an integer) such as 2.

[0011]

As described above, according to the reluctance type electric motor of the present invention, the stator, which is an armature, is provided on the inner peripheral surface side and the outer peripheral surface side of the cylindrical rotor that exhibits the sinusoidal inductance. Since it is provided, the output torque ripple is reduced and the rotation efficiency can be significantly improved. In addition, one of the two system stators is provided with a current command for the other system, which is phase-operated according to the current command map in the memory, based on the rotor position and speed, to the motor winding of the one system stator. Therefore, step-out can be prevented, and more stable control can be performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional structural view showing an example of a reluctance type electric motor of the present invention.

FIG. 2 is a partial vertical sectional structural view of a reluctance type electric motor of the present invention.

FIG. 3 is a perspective view showing details of a rotor of the reluctance type electric motor of the present invention.

FIG. 4 is a diagram showing a change in inductance in a rotating direction of a rotor of a reluctance type electric motor of a conventional type and the present invention.

FIG. 5 is a block diagram showing an example of a control device of the reluctance type electric motor of the present invention.

FIG. 6 is a cross-sectional structural view showing an example of a conventional reluctance type electric motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic pole constituent 2 Resin 3 Shaft body 4 External stator 5 Internal stator 6 Axis 7 Bearing 8, 11 Disk 10 Rotor 20, 21 Flange 23 Internal winding 24 External winding 31, 32 Protective material 51 Subtractor 52 Speed Controller 53 Current control circuit 54 Current control circuit 57 Current phase control unit 58 Memory 61 Rotor 62 Stator 63 Axis 70 Position detection means 71 Detector 72 Rotor position detection circuit 73 Speed detection circuit 80 Current command calculation means 81 Field Current command section 82 Armature current command section 83 Current command calculation section

Claims (4)

[Claims] 1. A reluctance type motor having a hollow cylindrical structure in which a plurality of magnetic material plates each having a salient pole so that an inductance change has a sine wave shape in a rotation direction are laminated in a rotation axis direction. A reluctance type electric motor characterized by being equipped with. 2. A rotor according to claim 1, further comprising a first stator disposed on the outer peripheral surface side of the rotor and a second stator disposed on the inner peripheral surface side of the rotor. Reluctance type electric motor. 3. The ratio of the number of teeth of the first stator to the number of teeth of the second stator is n: m (n ≧ m, n and m are integers of 10 or less). The reluctance type electric motor according to 1. 4. A computing means for computing a field current command and an armature current command is provided in one of the first stator and the second stator, and the other stator is provided in front of the other. Control means is provided for referring to the detected position and the detected speed of the rotor and for controlling the current phase based on the output from the arithmetic means, and is sent to the winding of the one stator by the output from the arithmetic means. The reluctance type electric motor according to claim 2 or 3, wherein the current is controlled, and the current sent to the winding of the other stator is controlled by the output from the control means.