JPH0538143A - Controller of cyclo converter - Google Patents

Abstract

(57) [Summary] [Object] The present invention makes the reactive power amount generated by the cycloconverter constant, and the reactive power amount generated by the cycloconverter is constant, so that the power factor of the system is set to 1 by a capacitor of the same capacity. The purpose is to do. [Configuration] Reactive power detection value V _AR ^- and reactive power setting value V _AR
^According to the deviation from ^* , the circulating current correction value _ice ^* output from the reactive power controller 16 and the cycloconverter 1
3 from the sum of the circulating current feedback i _c ⁻ detected by the circulating current detection circuit 17 and the circulating current set value i _c ^* according to the torque current feedback i _q ^* and the rotation speed ω _r ⁻ of the electric motor 36. In the gate controller 11, the AC voltage set values V _R ^* , V _S ^* , and V _T ^* are added to the circulating current control voltage V _c ^* obtained by the circulating current controller 18, and the positive group converter 41 forming the cycloconverter is added. , And a gate control signal for the negative group converter 42 are generated and output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cycloconverter control device.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a circuit configuration of a conventional circulating current type cycloconverter control device. In the figure, 1 is a speed setter, 2 is a speed controller, 3 is a magnetic flux command calculator, A magnetic flux controller 4 constitutes a current command value generation circuit 52 for the d-axis and the q-axis.

Reference numeral 7 is a vector rotator, and 9 is a 2φ / 3φ coordinate converter comprising an operational amplifier. The vector rotator 7 and the 2φ / 3φ coordinate converter 9 are the three-phase AC voltage setting device 53.
Are configured. 11 is a gate controller for armature current,
12 is an AC power supply, 13 is a three-phase circulating current type sine wave cycloconverter, and 22 is a proportional-integral amplifier.
An axis current controller, 23 is a d-axis current controller composed of a proportional-integral amplifier, 24 is a first-order delay calculator,
25, 27, 28 are multipliers, 5, 26, 30, 40 are fixed gains, 29 is a divider, 31 is an integrator, and 32 is a speed detector.

Reference numeral 33 is a sine wave and cosine wave generation circuit, 34 is a vector rotator, and 35 is a 3-phase / 2-phase conversion circuit. The vector rotator 34 and the 3-phase / 2-phase conversion circuit 35 are
The signal generating circuit 51 of FIG. 36 is a three-phase induction motor, 37 is a resolver, 15 is a VAR detector, and 16 is a reactive power control circuit.

Next, the operation will be described. Resolver 37
And the rotor speed feedback amount ω _r detected by the rotor speed detection circuit 32 enters the speed controller 2 and the magnetic flux command calculator 3. The speed controller 2 outputs a signal such that the rotor speed feedback value ω _r becomes the target value ω _r ^* as the q-axis current setting value i _q ^* .

Then, the three-phase output current i of the induction motor 36
_{After R} , i _S , and i _T are converted into two-phase alternating currents iα and iβ by the three-phase / two-phase conversion circuit 35, the vector rotator 34 linearly intersects the secondary magnetic flux as a value of the secondary magnetic flux rotation coordinate system. q-axis component current feedback is given as the flow rate value i _q ^-
And a deviation ε _q between the q-axis current setting value i _q ^* enters the q-axis current controller 22.

Next, the q-axis current controller 22 outputs the result of the proportional-plus-integral calculation as a q-axis voltage command V _q ^* . In the magnetic flux controller 4, the output Φ ^* of the magnetic flux command calculator 3 and the d-axis current feedback value id ⁻
The deviation from the output Φ ⁻ of the first-order delay calculator 24 with respect to is input and the d-axis shunt splitting set value id ^* is output.

Then, the three-phase output current i of the induction motor 36
_{After R} , i _S , and i _T are converted into two-phase alternating currents iα and iβ by the three-phase / two-phase conversion circuit 35, the vector rotator 34 linearly parallels the secondary magnetic flux as the value of the secondary magnetic flux rotation coordinate system. D-axis current feedback value id given as the flow rate
The deviation ε _d between ⁻ and the d-axis current setting value id ^* enters the d-axis current controller 23.

Next, in the d-axis current controller 23, the result of the proportional-plus-integral calculation is used as the d-axis voltage command value V _d ^*.
Output as. The secondary magnetic flux direction signals sin θ ₀ and cos θ ₀ need to be obtained in order to obtain the three-phase AC voltage setting value required to obtain the gate signal from the parameters obtained above.

The secondary magnetic flux phase θ ₀ is the angular frequency ω of the rotating magnetic field.
_It is calculated by integrating ₀ . And asked 2
The secondary magnetic flux direction signals sin θ ₀ and cos θ ₀ are obtained by the sine wave and cosine wave generation circuit 33 that receives the secondary magnetic flux phase θ ₀ as an input.

The output V _q ^* of the q-axis current regulator 22 is compensated for the interference term and the induced voltage term v _q ^*, and the output V _d ^* of the d-axis current controller 23 is compensated for the interference term. V _d ^*
Is a two-phase AC voltage Vα by the vector rotator 7 using the secondary magnetic flux direction signals sin θ ₀ and cos θ ₀ as parameters.
^* , Converted to Vβ ^* . The 2-phase / 3-layer converter 9 has the above-mentioned 2
Three-phase AC voltage set value V from the phase AC voltages Vα ^* and Vβ ^*
_R ^*, V _S ^*, and outputs the V _T ^*.

On the other hand, the circulating current detection circuit 17 detects the current of the positive group converter 42 and the current of the negative group converter 41,
Circulating current feedback i _c ^- obtained. The reactive power feedback V _AR detected by VAR detector 15 ^-
And the reactive power set value V _AR ^* are input to the reactive power controller 16 and the circulating current correction value i _ce ^* is output. The circulating current correction value i _ce ^* a circulating current set value i _c ^* of the sum and the circulating current feedback i _c ^- deviation i _c epsilon of is inputted to the circulating current controller 18 to obtain a circulating current control voltage V _c ^*.

The three-phase AC voltage set values V _R ^* , V _S ^* , and V _T ^*
Is supplied to the gate control device 11 for each phase of R, S, and T. In the gate control device 11 for each phase, the AC voltage setting value V
The sum of ^* and the circulating current control voltage V _c ^* is calculated, and the output voltage set value V ^* _F of the positive group converter 42 is entered into the gate pulse generation circuit in the gate control device 11 to set the AC voltage set value V ^*. The circulating current control voltage V _c ^* is subtracted from the inverted value, and the result is input to the gate pulse generation circuit 42 as the output voltage set value V ^* _R of the negative group converter 47.

The R, S, and T phases turn on the gates of the positive group converter 46 and the negative group converter 47, respectively, so that the three-phase cycloconverter 13 outputs three output voltages V _R , V _S , and V _T. phase AC voltage set value V _R ^*, V _S ^*,
V _T ^* and operates to match and each phase of the circulating current i _c ^-
Also operates so as to match the circulating current set value i _c ^* (constant value).

[0015]

Since the conventional cycloconverter control device is constructed as described above, the amount of the reactive power changes according to the output and the rotation speed of the induction motor, while the circulating current is changed. Since the set value i _c ^* is a constant value, there has been a problem that the operation range of the controller of the reactive power control for keeping the power factor of the system at 1 is wide and cannot be sufficiently followed.

The present invention has been made in order to solve the above-mentioned problems, and provides a cycloconverter having a responsive reactive power control in which a circulating current set value is set according to a variation amount of the reactive power. The purpose is to obtain a control device.

[0017]

A control device for a cycloconverter according to the present invention includes a circulating current correction value output from a reactive power controller according to a deviation between a reactive power detection value and a reactive power set value, and a circulating current from a cycloconverter. Circulating current feedback detected by the current detection circuit,
A cycloconverter is configured by adding the AC voltage set value in the gate controller to the circulating current control voltage obtained from the circulating current controller that performs the current feedback for the torque component of the electric motor and adds the circulating current set value according to the rotation speed. Generates and outputs a gate control signal for the positive group converter and the positive group converter.

[0018]

In the circulating current setting device of the present invention, the circulating current setting value, which has been a fixed value in the past, is changed according to the rotation speed and the torque load amount of the induction motor, which reduces the operating range of the reactive power control controller. Therefore, the response of the reactive power control becomes faster.

[0019]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the circulating current setting device 19
Has been added. The circulating current setting device 19 receives the torque-based current feedback i _q ⁻ and the rotational angular velocity ω _r ⁻ .

Next, the operation will be described. Since the entire operation is the same as that in FIG. 2, the reactive power constant control will be described focusing on the operation of the circulating current setting device 19. Circulating current setter 19 to the torque current feedback i _q ^- and the motor rotational angular velocity omega _r ^- are input, by referring to the two-dimensional table which VAR is set so as to become a constant, i _q ^-
And the circulating current set value i _c ^* corresponding to ω _r ⁻ and ω _r ⁻ are obtained. Since i _c ^* is set so that VAR becomes constant as described above, basically V _AR ^* and V _AR ⁻ are the same, and the output of the reactive power controller is 0. Therefore, the reactive power controller operates only transiently.

[0021]

As described above, according to the present invention, since the circulating current set value is set so that the amount of reactive power becomes constant, the reactive power set value and the reactive power detected value become the same, and The output of the power controller is zero. Therefore, the reactive power controller operates only transiently, so that a system with a fast response can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a control device for a cycloconverter according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional cycloconverter control device.

[Explanation of symbols]

 11 Gate Control Device 15 VAR Detector 16 VAR Control Controller 18 Circulating Current Controller 19 Circulating Current Setting Device 36 Electric Motor

Claims (1)

Claim: What is claimed is: 1. A circulating current type cycloconverter using an induction motor as a load, a reactive power detector for detecting reactive power from an AC input of the cycloconverter, and a reactive power detection value. A reactive current controller that generates and outputs a circulating current correction value, a circulating current setter that obtains a circulating current set value corresponding to the torque current feedback value and the rotational angular speed of the induction motor, and a circulating current feedback from the cycloconverter. A circulating current detection circuit, a circulating current controller for obtaining a circulating current control voltage from the circulating current feedback, a circulating current correction value, and a circulating current set value, an AC voltage command value for the cycloconverter, and a cycloconverter based on the circulating current control voltage. And a gate control device for obtaining a gate control signal to Cycloconverter controller according to.