JPH07110153B2 - Inverter controller for drive control of two-phase induction motor - Google Patents

Description

The present invention relates to a control device for driving an induction motor (including a linear motor) having a two-phase rotating magnetic field by a variable frequency power supply.

[Prior Art] When a two-phase induction motor is driven by a variable frequency power source,
Conventionally, the two-phase windings of a two-phase induction motor have two independent windings, and two two-phase inverters for driving a single-phase load are used to set the frequency and current to the two-phase windings. The control was performed so that a two-phase alternating current corresponding to the flow was applied.

FIG. 2 is a block diagram showing the control principle of drive control of a general two-phase induction motor.

Reference numeral 13 in FIG. 2 is an induction motor having independent windings for α and β, and each winding has a single-phase inverter 10
It is connected to A and 10B. In this circuit configuration, α
The currents iα and iβ flowing through the phase and β phase windings are Two single-phase inverters so that two-phase alternating current becomes
A current command signal is given to 10A and 10B to control.

Here, I is the effective value of the current flowing through the two-phase induction motor, f is the frequency of the current, and t is the time.

The operation will be specifically described based on the configuration of FIG. When the frequency f of the two-phase AC commanded by the frequency commander 1 is input to the two-phase oscillator 2, the two-phase AC command signal from the two-phase oscillator 2 corresponding to the frequency f. Are output, and those signals are input to the multipliers 3 and 5.

On the other hand, the signal instructed by the RMS current command unit 4 is input to the multipliers 3 and 5, and as a result, the α-phase current command signal is output from the multipliers 3 and 5. Phase current command signal Is output. These current command signals and current detector 1
The signal of the difference between the feedback currents iα _F and iβ _F due to 1, 12 is input to the current controllers 6 and 7, and the amplified signal is used as the current control signal.
PWM controllers 9A and 9B for α-phase and β-phase single-phase inverters
To enter. The PWM controllers 9A and 9B for single-phase inverters receive the current control signals, respectively, and switch the power transistors of the single-phase inverters 10A and 10B in accordance with known single-phase sine wave PWM control. By the switching, the voltage of the DC power supply 14 generated by rectifying the commercial AC power supply 15 is applied to each phase winding of the two-phase induction motor 13, and the α phase winding corresponds to the current command value iα _R. Current Flows. Similarly, the current in the β-phase winding is Current flows.

The above is the embodiment to which the conventional two-phase inverter is applied.

[Problems to be solved by the invention]

In the conventional control method described above, in order to control the two-phase induction motor by the variable frequency power source, the single-phase inverter 2
A two-phase inverter constructed by combining the stands was required.

Since the two-phase inverter is rarely applied only for a special purpose, there is a problem that the application cost of the two-phase inverter is too high. Further, since the two single-phase inverters are used, there is a problem that the external dimensions of the drive control device become too large.

The present invention has been made in view of such conventional problems, and it is an object of the present invention to reduce the outer dimensions and lower the equipment cost by simplifying the configuration.

[Means for solving problems]

In order to achieve this object, a drive control inverter control device for a two-phase induction motor according to the present invention is a drive control device for controlling a two-phase induction motor by a variable frequency power source, wherein a two-phase winding end of the two-phase induction motor is used. One of them is connected in common, and the common line and the other of the two-phase winding ends are connected to a three-phase inverter so that the two-phase alternating current required by the two-phase induction motor flows through the three-phase inverter It is characterized in that it is provided with a means for controlling.

〔Example〕

Hereinafter, the present invention will be specifically described based on the embodiments shown in the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, components having the same functions as those of the conventional configuration shown in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

First, the control principle of the present invention will be described.

In a drive control device for controlling a two-phase induction motor with a variable frequency power supply, if a means for supplying a two-phase alternating current to a winding of the induction motor is provided in accordance with a commanded frequency and current, a two-phase induction motor, Known vector control, V /
Control such as F control can be easily realized.

Next, the principle of control using a three-phase inverter to flow a two-phase alternating current according to the frequency and current instructed to the two-phase winding will be described.

Reference numeral 13 in FIG. 1 denotes an induction motor having a two-phase winding of α and β, one of the ends of the windings α and β is connected to the three-phase inverter 10, and the other end of the winding is common. Connect it to γ
Consider the current flowing in each phase in the circuit configuration connected to the inverter 10 as a phase.

The instantaneous values iα, iβ of the currents flowing in the α-phase and β-phase windings are expressed as follows.

Where I is the effective value of the current flowing in the two-phase induction motor, f
Is the frequency of the current and t is time.

There is the following relationship between the instantaneous value iγ of the current flowing in the γ phase and iα, iβ.

iα + iβ + iγ = 0 From this relationship, iγ is expressed as follows.

From the above, the α phase in the β phase By controlling the three-phase inverter so that the current of iγ = -2 Isin (2πft-π / 4) flows in the γ-phase, the two-phase AC current corresponding to the commanded frequency and current is induced in the two-phase. It can be seen that it is possible to feed the α-phase and β-phase windings of the electric motor 13.

Next, a detailed description of the embodiment shown in FIG. 1 will be given.

When the frequency f of the two-phase alternating current commanded by the frequency commander 1 is input to the two-phase oscillator 2, the two-phase alternating current signal from the same oscillator 2 according to the frequency f. When Are output, and those signals are input to the multipliers 3 and 4.

On the other hand, the signal commanded by the RMS current command unit 4 is input to the multipliers 3 and 4, and as a result, the α-phase current command signal is output from the multipliers 3 and 4. β-phase current command signal Are output respectively.

Instantaneous feedback current value iα _F proportional to the current command value iα flowing in the α phase of the induction motor 13 detected by the α-phase current detector 11
And the α phase current command value i α _R
To enter.

The input deviation signal (iα _R -iα _F) is amplified by α phase current controller 6, an output signal is input to the three-phase inverter PWM controller 9 as α phase current control signal.

Similarly, for the β phase, the signal of the difference between iβ _R and iβ _F
Input to the phase current controller 7. The input deviation signal (iβ _R
-Iβ _F ) is amplified by the β-phase current controller 7, and its output signal is used as a β-phase current control signal for the three-phase inverter.
It is input to the PWM controller 9.

Next, the γ-phase current command will be described.

The signals of iα _R and iβ _R are inverted and the sum signal is used as the γ-phase current command signal iγ _R.

That, i? _R = - a (iα _R + iβ _R).

In addition, the sum of the signals obtained by inverting the signal of iα _F + iβ _F is iγ
_Let it be _F.

That is, iγ _F = − (iα _F + iβ _F ).

Furthermore, i? _R and i? _F of the difference signal γ phase current controller 8
To enter.

The PWM controller 9 for the three-phase inverter receives the current control signals of α, β and γ phases and receives the known sine wave PWM of α phase, β phase and γ phase.
According to the control, the α-phase, β-phase, and γ-phase power transistors of the power transistor 10 of the three-phase inverter are switched. By its switching, the voltage of the DC power supply 14 is applied to each phase winding of the induction motor 13, the α-phase in accordance with the current command value i? _R current Flows. Similarly, for the β phase A current of iγ = −2 Isin (2πft−π / 4) flows in the γ phase.

〔The invention's effect〕

As described above, in the present invention, when one of the α-phase and β-phase winding terminals of the two-phase induction motor is commonly connected and the common line is the γ-phase, the The three-phase inverter is used to control so that a combined value of the instantaneous current values of the phase and β-phase flows. As a result, the drive control device can be configured with one general three-phase inverter instead of the conventional special two-phase inverter configured with two single-phase inverters. Therefore, the equipment cost of the control device can be reduced, and the external dimensions of the drive control device can be reduced.

[Brief description of drawings]

FIG. 1 is a control principle block diagram of a two-phase induction motor drive control inverter according to the present invention, and FIG. 2 is a single-phase inverter 2
It is a control principle block diagram of the conventional two-phase inverter comprised by combining the stands. 1: Frequency command device, 2: Two-phase oscillator 3, 5: Multiplier, 4: Current command device 6: α-phase current controller, 7: β-phase current controller 8: γ-phase current controller, 9: Three -Phase PWM controller 10: Power transistor for 3-phase inverter 11: α-phase current detector, 12: β-phase current detector 13: Two-phase induction motor, 14: DC power supply 15: Commercial AC power supply

Claims (1)

[Claims] 1. A drive control device for controlling a two-phase induction motor by a variable frequency power source, wherein one of the two-phase winding ends of the two-phase induction motor is connected in common, and the common line and the two-phase winding end are connected. The other of the two is connected to a three-phase inverter, and means for controlling the two-phase induction motor to flow a two-phase alternating current required by the two-phase induction motor by driving the two-phase induction motor. Inverter control device for control.