JPS62193593A - Control system of reluctance motor - Google Patents

Abstract

PURPOSE:To simplify a control device, to reduce cost, and to eliminate electromagnetic noise or vibration, by a method wherein a reluctance motor is controlled by a control device similar to a three-phase AC servo motor. CONSTITUTION:Command signals to windings phi1, phi2 are generated using a two-phase current command generating circuit B'. The command signal and actual current of each winding are compared, and command signal to control element is formed based on the deviation signal as comparison result by an error amplifier C, a pulse width modulation circuit (PWM) D, a drive circuit E. In this constitution, control is effected so that resultant value of instantaneous value of current of each winding is made zero, and ripple component of torque of positive direction generated by current of winding of one phase is removed by torque or negative direction in other two phases, thereby resultant torque of constant value in positive direction is obtained.

Description

[Detailed description of the invention] (Industrial application field) -k A:8nn I+ I+;/7
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(Prior Art) A reluctance motor, which is a type of magnet-type synchronous motor, has characteristics such as being able to easily maintain a constant speed in synchronization with a power supply frequency. FIGS. 4(a) and 4(b) show three-phase stator windings φ1 and φ2.

FIG. 3 is a block diagram of a control circuit for a reluctance motor having a diameter of φ3. In Figure (a), a speed command signal and an actual speed signal of the motor are compared by a comparator F1, and a deviation signal is input to a speed controller A. A torque command signal is generated from the speed controller A and inputted to the three-phase current command generation circuit B. The three-phase current command generation circuit includes windings φl and φ2 of each phase.
．． Outputs command current for φ3. Figure (b) shows φ1
Tit flow key control lock diagram for the winding, other φ2.
The φ3 winding has a similar configuration. The command current signal of the φ1 winding and the actual current signal of the φ1 winding are determined by the comparator F2.
The difference signal is input to the error amplifier C. Deviation signal amplified by error amplifier 1P 11/
S#A4T3 21) [1ν* /PWM
) rl17 1-h"r?+ A control current command signal for each winding is input to the drive circuit E. The drive circuit provides a control signal to a control element composed of, for example, a transistor.

Figure (C) is an example of a control circuit using a transistor inverter. When the transistors Trl and Tr2 are turned on, a current flows through the winding φ1, and by changing the bias of each transistor, the current value of the winding φ1 can be controlled.

(Problems to be solved by the invention) In this way, the conventional reluctance motor control circuit is
Since a control device as shown in FIG. 4(b) was provided for each winding, there were problems in that the device became complicated and the cost increased. In addition, when Trl and Tr2 are turned off in order to cut off the current to the φ1 winding at 4 (b) in the same figure, the charge in the capacitor CO is transferred to the diode d.
2. It flows through the φ1 winding through d1. The transient current at this time rises rapidly due to a certain number determined by the capacitor capacity and winding reluctance, turning on the control transistor and
When off, a high chopper frequency will occur,
There was a problem that magnetic noise, vibration, etc. were generated. Furthermore, the output torque from the reluctance motor is a combination of output torques from each winding, and includes ripple components, which poses a problem in that stable control cannot be performed.

Therefore, the present invention solves the above-mentioned conventional problems by controlling a reluctance motor in the same way as a three-phase AC servo motor.

(Means for Solving the Problems) The present invention is a control system for a reluctance motor having a three-phase stator winding, in which a torque command signal is formed by a deviation signal between a speed command signal and an actual speed signal, and the stator A rotor position signal for the windings forms a current command signal for each phase winding corresponding to the torque command signal, and a deviation signal between the current command signal and the actual current of each winding drives a control element. , the composite value of the instantaneous values of the currents in each winding becomes zero, and the ripple component of the positive direction torque generated by the current in the one-phase winding is removed by the negative direction torque of the other two phases. The problems of the prior art described above are solved by providing a reluctance motor (7) control system that controls so as to obtain a constant value of resultant torque.

(Function) In the present invention, the reluctance motor is controlled by a control device similar to a three-phase AC servo motor, so the control device is simple and costs are reduced, and electromagnetic noise and vibration occur when the control element is turned on and off. does not occur. Furthermore, since the composite torque does not include ripple components, stable control can be performed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
Figures (a) and (b) are block diagrams of a control circuit for a reluctance motor of the present invention. In FIG. 1(a), the operation is similar to that of the conventional example in FIG. 4(a), except that the two-phase current command generation circuit B' is used to generate command currents to the φ1 and φ2 windings. Therefore, detailed explanation will be omitted. next,
As shown in (b) in the same figure, the command current and the actual current of each winding are compared, and the deviation signal is sent to the error amplifier C, the pulse width modulation circuit (PW
M) D. The drive circuit E forms a command signal to the control element. Here, the command current of the φ1 winding and the command current of the φ2 winding are input to the comparator G1, and the comparator G1
Calculate the command current for the 3rd winding. That is, it acts as a two-phase to three-phase converter. Similarly, the comparator G2 also operates as a two-phase to three-phase converter that calculates the current in the φ3 winding based on the actual φ1 and φ2 winding currents. In addition.

Fl, F2, F3, and F4 are comparators that compare the command current of each winding and the actual MX, current to form a deviation signal.

FIG. 2C shows an example of a control circuit that controls the current to each winding. A bridge in which diodes dl-d6 are connected in parallel to each of the transistors Trl to Tr6 constitutes a transistor in-line, and three-phase windings φl,
Connect to φ2.4)3 as shown in the diagram. For example, Trl
, Tr4 is turned on, current flows through the φl and φ2 windings. The current value at this time is controlled to an appropriate value by changing the bias of each transistor according to the command signal from the drive circuit. When only the transistor Tr,1 is turned off, the residual current flows in the direction of the arrow in the figure, but because the resistance and reluctance of the circuit are small, it attenuates rapidly. Subsequently, transistor Trl is turned off, and Tr5 is turned off.
．． Turn on Tr6, φ2. Supply current to φ3 winding. In this way, by controlling each winding current of the reluctance motor in the same way as an AC servo motor, the device becomes simple, and magnetic noise and vibration caused by turning on and off the control element can be suppressed.

FIGS. 2 and 3 are explanatory diagrams of torque generated by controlling the reluctance motor according to the present invention.

In FIG. 2, T l + 72 + T5 corresponds to each winding φ□, φ2 . It shows the torque generated when a constant current is passed through φ3. In addition, the current I of the φ1 winding is the broken line, the current I2 of the φ2 winding is a dashed line, and the current I of the φ3 winding is
5 is represented by a two-dot chain line. In the present invention, three-phase windings φ1, φ2. The sum of the instantaneous flows 11f flowing to φ3 is controlled to be zero, and the combined torque is controlled to be a constant torque.

T2. It controls I3.

Below, I, I2. ■Explain the control of Party B. 11, the angle of the rotor is θ. ~o5 is a constant positive current, and from 03 to θ4, the current is reduced, and θ, 1
The current is zero between .theta.5, gradually increases in the negative direction from 05 to .theta.6, and is constant in the negative direction after .theta.6. The torque of the φ1 winding at this time becomes T1' in FIG. That is, for angles between 0° and 03, the positive direction (clockwise direction)
A torque like the triangle 0+P1+02' is generated. When work 1 gradually decreases from 03 to θ4, triangle 02
', P2'', 92' generates a negative (counterclockwise) torque. This triangle 02'.

The area of P2'', q2' is figure 02', P2'.

Control so that it is equal to q2', P2''.04~θ
At an angle of 5, T1'=O, and from 05 to θ6 produces a torque corresponding to the triangle 05',',q5' (the area of which is equal to the figure o5' + P5' + q5'+ Ps'') .Furthermore, after θ6,
The torque increases again in the positive direction. Similarly, the torque T2' due to the electric current fU I 2 of the φ2 winding corresponds to the triangle 01', P1 + ql' at the angle θl to θ2, and the torque ql in the positive direction of the triangle at the angle 02 to θ5.
'+ P2 * 05 ', triangular 0 in 05~O6
A torque of 5'+''+q3' is generated.The torque T3' caused by the electrician 3 of the φ5 winding is the angle O1~02
Then, a torque corresponding to the triangle Ot'+91'', (11' is generated, but this torque is 1 figure 01'+
It is equal to the torque corresponding to Pl ′・ql ′・pl ″.

Therefore, between the angles θl and θ2, the currents I2 and 13
The negative torque due to triangle 01'+P+”+(i
Torque corresponding to t' and figure 01'+Pt
' , ql ', and Pl '' are combined, and the size corresponds to the triangle 0 + ' + Pt ' + q□ '. This triangle O1 + Pi in the negative direction
Since the size of '+(it' and the triangles 0+, Pt, and qt due to the positive direction torque are equal, the torque corresponding to the triangle Of-, p1.(11) will be canceled out and removed.Similarly, , triangle 02 , P2
, (12, and 05. The torque corresponding to Ps, q5 is also canceled, and the torque T1', "r2'.

By combining I3', a constant torque Ta is obtained.

In addition, the triangle Or ′, Pt”・(It ′) in the negative direction
(Thus, the resultant torque between this angle due to the two out-of-phase currents is the triangle Oz', Pt'+qt
A torque of a magnitude corresponding to 1) can be easily generated by applying a control signal from a drive circuit to a control element such as a transistor so as to obtain a preset torque pattern.

(Effects of the Invention) As described above, according to the present invention, since the reluctance motor is controlled by current control similar to that of a three-phase AC servo motor, the control equipment is simple and the cost can be reduced. Furthermore, magnetic noise and vibrations when the current control element of the reluctance motor is turned on and off can be suppressed. Furthermore, since the generated torque does not include ripple, stable control is possible.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are block diagrams of the present invention, and FIG.
c) is a circuit diagram of the present invention, FIGS. 2 and 3 are characteristic diagrams of the present invention, FIGS. 4(a) and 4(b) are block diagrams of the conventional example, and FIG.
Figure (C) is a circuit diagram of a conventional example. A: Speed controller, B: Three-phase current command generation circuit,
B'...Two-phase current command generation circuit, C...Error amplifier. D... Pulse width modulation circuit (PWM), E... Drive circuit, F1 to F4... Comparator, G, , G2... Comparator (two-phase to three-phase conversion circuit). Patent applicant: Fanuc Co., Ltd. Agent: Patent attorney: Mr. Tsuji Company Figure 4 (C)

Claims (1)

[Claims] In a control method for a reluctance motor having a three-phase stator winding, a torque command signal is formed by a deviation signal between a speed command signal and an actual speed signal, and a rotor position signal with respect to the stator winding is used to form a torque command signal. A current command signal is formed for the corresponding winding of each phase, and a control element is driven by a deviation signal between the current command signal and the actual current of each winding, so that the composite value of the instantaneous values of the current of each winding becomes zero. At the same time, the ripple component of the positive direction torque generated by the current in the single-phase winding is
A control method for a reluctance motor, characterized in that the reluctance motor is controlled so that a composite torque of a constant value in the positive direction is obtained by removing the negative direction torque of other two phases.