JPH11134042A - Ac power regulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC power regulator, with which more stabilized power can be supplied to the load of a device, by suppressing the fluctuation in the output voltage of the AC power regulator corresponding to a rapid change in the voltage of an AC power source through a differentiation circuit. SOLUTION: A control circuit 40 turns the output of a differentiation circuit 42 into (+) polarity when the voltage of an AC power source 1 is rapidly lowered, and turns it into (-) polarity when the voltage of the AC power source 1 is rapidly increased. Then, an addition computing element 43 adds the output of the differentiation circuit 42 and the output of a voltage regulator 23 for performing regulating operation based on the deviation of an output voltage setting value and an output voltage detecting value. Thus, the rapid change in the voltage of the AC power source 1 is compensated and based on the setting value of a voltage setter 21, the almost fixed voltage is supplied to a load 2. Therefore, even when the AC power source is rapidly changed or hit failure occurs, the fluctuation in the output voltage of such an AC power regulator 30 is suppressed and as a result, the stabilized power can be supplied to the load 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC power regulator for supplying a desired AC power to a load at the same frequency as an AC power supply such as a commercial power supply.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional example of this type of AC power adjusting apparatus, wherein 1 is an AC power supply such as a commercial power supply, 10 is an AC power adjusting apparatus, and 2 is an AC power adjusting apparatus. Show the load of The AC power regulator 10 includes a reactor 11 and a capacitor 12 as an input filter, and a main circuit 13 in which six sets of semiconductor switches, each of which is an anti-parallel circuit of an IGBT and a diode as a self-extinguishing element, are bridge-connected, A reactor 14 and a capacitor 15 as output filters, a voltage detector 16 for detecting a voltage across the capacitor 12, that is, an input voltage (AC amount) of the AC power regulator 10, and a voltage detector 16 for detecting the voltage across the capacitor 15, that is, the AC power regulator 10 A voltage detector 17 for detecting an output voltage (AC amount) and the respective semiconductor switches constituting the main circuit 13 for supplying desired AC power to the load 2 at the same frequency as the AC power supply 1 are turned on.
And a control circuit 20 for performing off control. The intermediate connection point of the first arm (the arm on the left side of FIG. 4) of the bridge-connected main circuit 13 is connected to one end of the AC power supply 1 via the reactor 11, and the third arm of the main circuit 13 (FIG. The intermediate connection point of the arm on the right side of the drawing is connected to one end of the load 2 via the reactor 14, and the intermediate connection point of the second arm of the main circuit 13 (the arm on the center of the drawing in FIG. 4) and the AC power supply 1
And the other end of the load 2 are connected in parallel.

The control circuit 20 converts an output voltage set value (DC amount) set by a voltage setter 21 and an output (AC amount) of a voltage detector 17 through a rectifier circuit 22 including a rectifier and a filter. A voltage adjuster 23 that performs an adjustment operation based on a deviation from the obtained output voltage detection value (DC amount), and a PLL (phase lock loop) circuit that outputs a reference sine wave signal synchronized with the phase of the output of the voltage detector 16 24, a sine wave command generator 25 for multiplying the reference sine wave signal by the set value of the voltage setting device 21 and outputting the output voltage set value (AC amount), and the output voltage set value (AC amount). An addition calculator 26 for calculating a deviation from the output of the voltage detector 17, an addition calculator 27 for adding the output of the voltage regulator 23 and the output of the addition calculator 26, and an output of the addition calculator 27 and a carrier signal. Pulse distribution which outputs an ON / OFF signal of each of the semiconductor switches of the main circuit 13 based on the calculated value and a zero-cross signal generated from the output of the voltage detector 16. And a gate drive circuit 29 for generating a gate signal of each IGBT constituting the semiconductor switch based on the ON / OFF signal.

[0004] In the AC power regulator 10 shown in FIG.
When making the voltage (Vo) supplied to the load 2 higher than the voltage (Vi) of the AC power supply 1 (Vo> Vi), the pulse width modulation (PWM) by the output of the adder 27 and the carrier signal is used. ) An operation is performed, and this operation value and the voltage detector 16
For each of the semiconductor switches of the main circuit 13 based on the zero-cross signal generated from the output of
The upper and lower semiconductor switches of the first arm are alternately turned on and off based on the PWM operation value and the zero cross signal, and the upper and lower semiconductor switches of the second and third arms are based only on the zero cross signal. Turn on and off alternately.

Further, the voltage (Vo) supplied to the load 2 is made lower (Vo) than the voltage (Vi) of the AC power supply 1.
<Vi), the upper and lower semiconductor switches of the third arm are alternately turned on and off based on the PWM operation value and the zero cross signal, and the upper and lower semiconductor switches of the first and second arms are turned off. Are turned on and off alternately based only on the zero-cross signal.

Further, when making the voltage (Vo) supplied to the load 2 substantially equal to the voltage (Vi) of the AC power supply 1 (Vo ≒ Vi), the PWM operation is deactivated,
The upper and lower semiconductor switches of the first to third arms are alternately turned on and off based on only the zero cross signal.

[0007]

In the conventional AC power regulating apparatus 10 shown in FIG. 4, the voltage of the AC power supply 1 changes suddenly (for example, suddenly drops, rises or recovers) due to a system failure of the AC power supply 1, for example. ), The output voltage of the AC power regulator 10 is corrected at a response speed of about several hundred milliseconds. If the time constant of the filter included in the rectifier circuit 22 is reduced in order to improve the response speed, there is a problem that the output voltage of the AC power regulator 10 fluctuates even during normal times.

When the voltage of the AC power supply 1 rises sharply,
The output voltage of the AC power adjusting device 10 also has a short-time sudden increase (overvoltage), and there is a possibility that the equipment constituting the load 2 may be damaged by the overvoltage. Further, when an instantaneous power failure occurs in the AC power supply 1, there is a problem in that the PLL circuit 24 and the sine wave command generator 25 are disturbed, and the waveform distortion of the output voltage of the AC power regulator 10 is sharply increased. When an instantaneous power failure occurs, the AC power supply 1 is determined to be abnormal and the AC power regulator 10 is stopped.

An object of the present invention is to solve the above-mentioned problems and to provide an AC power adjusting device capable of supplying more stable power to a load of the device.

[0010]

According to a first aspect of the present invention, six sets of semiconductor switches each having a self-extinguishing element and a diode connected in anti-parallel are bridge-connected, and the first connection of the bridge connection is provided.
The intermediate connection point of the arm is connected to one end of the AC power supply via the input LC filter, the intermediate connection point of the third arm of the bridge connection is connected to one end of the load via the output LC filter, and the third connection point of the bridge connection is provided. The intermediate connection point of the two arms, the other end of the AC power supply, and the other end of the load are connected in parallel, and the respective semiconductor switches are turned on / off by a control circuit, so that a desired AC is applied to the load at the same frequency as the AC power supply In the AC power regulating device for supplying power, the control circuit includes a voltage regulator for performing a regulation operation based on a deviation between an output voltage set value (DC amount) and an output voltage detection value (DC amount) of the device. A differentiating circuit for calculating a differential value of an input voltage detection value (a direct current amount) of the device, a first addition calculator for adding an output value of the voltage regulator and a calculated value of the differentiating circuit, and an output voltage setting of the device Value (AC amount) Third adding a second adding calculator for calculating a deviation between the output voltage detection value (AC weight), the calculated value of the first adders and the calculated value of the second adders
And a pulse width modulation (PWM) operation using the operation value of the third addition operation unit and the carrier signal, and based on this operation value and the zero-cross signal generated from the AC power supply, A pulse distributor for turning on / off the semiconductor switch.

According to a second aspect of the present invention, in the AC power adjusting device, the control circuit performs an adjustment operation based on a deviation between an output voltage set value (DC amount) and an output voltage detection value (DC amount) of the device. A voltage adjuster, a first addition calculator for calculating a deviation between an output voltage set value (AC amount) and an output voltage detection value (AC amount) of the device, and a first addition to the output value of the voltage adjuster A second addition calculator for adding the calculation value of the calculation unit, and a pulse width modulation (PWM) calculation using the calculation value of the second addition calculation unit and the carrier signal, and generating the calculated value and the AC power. A pulse distributor for turning on / off each of the semiconductor switches based on the zero-cross signal to be performed, and operating when the output voltage detection value (AC amount) exceeds a peak value based on the output voltage set value. The comparator and the comparator Output when, after the comparator becomes inoperative also output a predetermined time, and a pulse-off circuit for preventing the output of the pulse distributor by this output.

According to a third aspect of the present invention, in the AC power adjusting device, the control circuit performs an adjustment operation based on a deviation between an output voltage set value (DC amount) and an output voltage detection value (DC amount) of the device. A voltage regulator; a first addition calculator for calculating a deviation between an output voltage set value (AC amount) and an output voltage detection value (AC amount) of the device; A phase difference switch that opens its contact when the phase difference with the AC power supply becomes equal to or more than a predetermined value; a calculated value of the first addition calculator via the contact of the phase difference switch and an output of the voltage regulator; A second addition operation unit for adding the calculated value, a pulse width modulation (PWM) operation based on the operation value of the second addition operation unit and the carrier signal, and a zero-cross signal generated from the AC power supply. And based on the respective semiconductor And a pulse distributor for turning on and off a switch.

According to the present invention, even when the AC power supply changes abruptly (suddenly drops, rises, or returns), or a momentary power failure occurs, the fluctuation of the output voltage of the AC power regulator is suppressed as described later. As a result, stable power can be supplied to the load. That is, according to the first aspect, the output voltage of the AC power regulator can be suppressed from fluctuating due to a sudden change in the voltage of the AC power supply by the differentiating circuit.

Further, according to the second aspect, the comparator and the pulse-off circuit prevent the output voltage of the AC power regulating device from rising sharply due to the sudden rise in the voltage of the AC power supply. Further, according to the third aspect, the phase difference switch can suppress an increase in waveform distortion of an output voltage of the AC power adjustment device due to an instantaneous power failure of the AC power supply.

[0015]

FIG. 1 is a block diagram of an AC power regulating apparatus according to a first embodiment of the present invention.
Those having the same functions as those of the conventional example shown in FIG. That is, FIG.
In this AC power adjusting device 30, the reactor 1
1, a capacitor 12, a main circuit 13, a reactor 14, a capacitor 15, a voltage detector 16, a voltage detector 17, and a control circuit 40.

The control circuit 40 includes a voltage setter 21, a rectifier circuit 22, a voltage regulator 23, a PLL circuit 24, a sine wave command generator 25, an addition calculator 26, a pulse distributor 28,
In addition to the gate drive circuit 29, a rectifier circuit 41 that converts the output (AC amount) of the voltage detector 16 into an input voltage detection value (DC amount) and calculates a differential value of the input voltage detection value (DC amount). It comprises a differentiating circuit 42 and addition computing units 43 and 44.

In the control circuit 40 shown in FIG. 1, the output of the differentiating circuit 42 has a positive polarity when the voltage of the AC power supply 1 drops sharply, and has a negative polarity when the voltage of the AC power supply 1 rises sharply. The addition operation unit 43 adds the output and the output of the voltage controller 23 that performs an adjustment operation based on a deviation between the output voltage set value (DC amount) and the output voltage detection value (DC amount), thereby obtaining AC power. An almost constant voltage based on the set value of the voltage setting device 21 is supplied to the load 2 by compensating for a sudden change in the voltage of the power supply 1.

FIG. 2 is a block diagram of an AC power regulating apparatus according to a second embodiment of the present invention, in which components having the same functions as those of the conventional block diagram shown in FIG. Therefore, the description is omitted. That is, in FIG. 2, the AC power adjusting device 50 includes a reactor 11, a capacitor 12, a main circuit 13, a reactor 14, a capacitor 15, a voltage detector 16, a voltage detector 17, and a control circuit 6.
0 is provided.

The control circuit 60 comprises a voltage setter 21, a rectifier circuit 22, a voltage regulator 23, a PLL circuit 24, a sine wave command generator 25, an adder 26, an adder 27, a pulse distributor 28, and a gate. In addition to the drive circuit 29, a peak voltage setter 61, a comparator 62, an off-delay circuit 63
And a pulse-off circuit 64. In the control circuit 60 shown in FIG. 2, a peak voltage setter 61 for setting the peak value of the output voltage from the set value of the voltage setter 21 is compared with the peak value and the output of the voltage detector 17, and the output is compared. The comparator 6 which operates when the spire value exceeds the peak value
2, an off-delay circuit 63 that outputs when the comparator 62 performs the above operation, and outputs for a predetermined time even after the comparator 62 becomes inoperative; and a pulse distribution when the off-delay circuit 63 outputs The output of the gate 28 is the gate drive circuit 2
9 prevents a sudden rise in the output voltage of the AC power regulator 50 due to a sudden rise in the voltage of the AC power supply 1, and is substantially constant based on the set value of the voltage setting unit 21. Voltage is supplied to the load 2.

FIG. 3 is a block diagram of an AC power regulator according to a third embodiment of the present invention, in which components having the same functions as those of the conventional block diagram shown in FIG. Therefore, the description is omitted. That is, in FIG. 3, the AC power adjusting device 70 includes a reactor 11, a capacitor 12, a main circuit 13, a reactor 14, a capacitor 15, a voltage detector 16, a voltage detector 17, a control circuit 8
0 is provided.

The control circuit 80 includes a voltage setter 21, a rectifier circuit 22, a voltage regulator 23, a PLL circuit 24, a sine wave command generator 25, an adder 26, an adder 27, a pulse distributor 28, and a gate. In addition to the drive circuit 29, the phase difference switch 8 whose contact is inserted into the output of the adder 26
1 is provided. In the control circuit 80 shown in FIG.
When the phase difference between the output voltage set value (AC amount) output from the sine wave command generator 25 and the output of the voltage detector 16 exceeds a predetermined value, a phase difference switch 81 that opens its contact. Thus, by preventing the output of the addition calculator 26 constituting the so-called instantaneous value correction control of the AC power adjustment device 70 from being input to the addition calculator 27, AC power adjustment due to an instantaneous power failure of the AC power supply 1 is prevented. The increase in the waveform distortion of the output voltage of the device 50 is suppressed, and a substantially constant voltage based on the set value of the voltage setting device 21 is supplied to the load 2.

[0022]

According to the present invention, even when the AC power supply changes abruptly (suddenly drops, rises or returns), or an instantaneous power failure occurs, the output voltage of the AC power regulating apparatus fluctuates as described above. As a result, stable power can be supplied to the load.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an AC power adjusting apparatus according to a first embodiment of the present invention;

FIG. 2 is a block diagram of an AC power adjusting apparatus according to a second embodiment of the present invention;

FIG. 3 is a block diagram showing an AC power regulating apparatus according to a third embodiment of the present invention;

FIG. 4 is a block diagram of an AC power adjusting apparatus showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... AC power supply, 2 ... Load, 10 ... AC power adjustment device, 1
DESCRIPTION OF SYMBOLS 1 ... Reactor, 12 ... Capacitor, 13 ... Main circuit, 1
4 reactor, 15 capacitor, 16 and 17 voltage detector, 20 control circuit, 21 voltage setter, 22 rectifier circuit, 23 voltage regulator, 24 PLL circuit, 25
Sine wave command generator, 26, 27 addition arithmetic unit, 28 pulse distributor, 29 gate drive circuit, 30 AC power regulator, 40 control circuit, 41 rectifier circuit, 42 differentiator circuit, 43 44 addition arithmetic unit, 50 AC power adjusting device, 60 control circuit, 61 peak voltage setting device, 62
Comparator, 63: Off-delay circuit, 64: Pulse-off circuit, 70: AC power regulator, 80: Control circuit, 81:
Phase difference switch.

Claims (3)

[Claims] 1. A bridge connection of six sets of semiconductor switches each having an anti-parallel connection of a self-extinguishing element and a diode. An intermediate connection point of a first arm of the bridge connection is connected to an AC power supply via an input LC filter. One end, the intermediate connection point of the third arm of the bridge connection is connected to one end of the load via an output LC filter, and the intermediate connection point of the second arm of the bridge connection, the other end of the AC power supply, and the load Connect the other end in parallel,
The respective semiconductor switches are turned on / off by a control circuit.
In an AC power regulating apparatus that supplies a desired AC power to a load at the same frequency as an AC power supply by performing off-control, an output voltage set value (DC amount) of the apparatus is provided in the control circuit.
A voltage controller for performing an adjustment operation based on a deviation between the output voltage detection value (DC amount) and a differential circuit for calculating a differential value of an input voltage detection value (DC amount) of the device; and an output value of the voltage controller. A first addition calculator for adding the calculated value of the differential circuit and a calculation value of the differentiation circuit; and a second addition calculator for calculating a deviation between an output voltage set value (AC amount) and an output voltage detection value (AC amount) of the device. A third addition operator for adding the operation value of the first addition operator and the operation value of the second addition operator, and pulse width modulation using the operation value of the third addition operator and a carrier signal. And a pulse distributor for turning on / off each of the semiconductor switches based on the calculated value and a zero-cross signal generated from the AC power supply. . 2. A bridge connection of six sets of semiconductor switches each having an anti-parallel connection of a self-extinguishing element and a diode. An intermediate connection point of a first arm of the bridge connection is connected to an AC power supply via an input LC filter. One end, the intermediate connection point of the third arm of the bridge connection is connected to one end of the load via an output LC filter, and the intermediate connection point of the second arm of the bridge connection, the other end of the AC power supply, and the load Connect the other end in parallel,
The respective semiconductor switches are turned on / off by a control circuit.
In an AC power regulating apparatus that supplies a desired AC power to a load at the same frequency as an AC power supply by performing off-control, an output voltage set value (DC amount) of the apparatus is provided in the control circuit.
And a voltage regulator for performing an adjustment operation based on a deviation between the output voltage detection value (DC amount) and an output voltage detection value (AC amount) of the device. 1, an addition operator for adding the output value of the voltage regulator and the operation value of the first addition operator, and a pulse based on the operation value of the second addition operator and a carrier signal A pulse distributor for performing a width modulation (PWM) operation and turning on and off the respective semiconductor switches based on the operation value and a zero-cross signal generated from the AC power supply; and an output voltage detection value (AC amount) A comparator that operates when a peak value based on the output voltage set value is exceeded, outputs when the comparator operates, and outputs for a predetermined time even after the comparator becomes inoperative. The output of the pulse distributor by the output AC power conditioner being characterized in that a pulse-off circuit for stopping. 3. A bridge connection of six sets of semiconductor switches each having an anti-parallel connection of a self-extinguishing element and a diode, and an intermediate connection point of a first arm of the bridge connection is connected to an AC power supply via an input LC filter. One end, the intermediate connection point of the third arm of the bridge connection is connected to one end of the load via an output LC filter, and the intermediate connection point of the second arm of the bridge connection, the other end of the AC power supply, and the load Connect the other end in parallel,
The respective semiconductor switches are turned on / off by a control circuit.
In an AC power adjusting device that supplies a desired AC power to a load at the same frequency as an AC power source by performing off-control, an output voltage set value (DC amount) of the device is provided in the control circuit.
And a voltage regulator for performing an adjustment operation based on a deviation between the output voltage detection value (DC amount) and an output voltage detection value (AC amount) of the device. 1, an addition arithmetic unit, a phase difference switch for opening a contact when a phase difference between the output voltage set value (AC amount) and the AC power supply is equal to or greater than a predetermined value, and the contact of the phase difference switch A second addition unit for adding the operation value of the first addition unit and the output value of the voltage regulator via the second addition unit, and pulse width modulation (PWM) using the operation value of the second addition unit and the carrier signal. A) a pulse distributor for performing an operation and turning on and off each of the semiconductor switches based on the operation value and a zero-cross signal generated from the AC power supply.