JP2003348843A - Ac power regulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly efficient AC power regulator by lessening spike voltages. <P>SOLUTION: In the power regulator, which is equipped with an AC switch 4 for output control provided between an input terminal 1a and an output terminal 3a and composed of a semiconductor element and a diode and an AC switch 5 for reflux provided between one end on the side of the output terminal 3a of the AC switch 4 for output control and a remote controller line Y and composed of a semiconductor element and a diode and takes out an arbitrary AC voltage from an input AC power source P prior to outputting, the AC switch 5 for reflux is operated with the same frequency as the frequency of input AC voltage. As a result, the generation cycle of spike voltages becomes the same as that of the input AC voltage, thus a highly efficient AC power regulator can be materialized. <P>COPYRIGHT: (C)2004,JPO

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 capable of continuously varying the output of a commercial input AC power supply from 0% to 100%.

[0002]

2. Description of the Related Art As means for extracting and outputting an arbitrary sine wave AC voltage from a commercial input AC power supply, an induction voltage regulator, a slide transformer, and a thyristor-controlled voltage regulator are known.

[0003] The above-described induction voltage regulator and slide transformer can continuously vary and output a sine wave AC voltage, and are therefore often used in research and experimental facilities and the like. However, since the principle is an autotransformer used for commercial frequency, both volume and weight are large. Further, since the output AC voltage is varied by sliding the windings, a step voltage between the windings is generated, and it is virtually impossible to output a completely continuous variable voltage.

[0004] Thyristor-controlled voltage regulators are widely used in home appliances, lighting devices, electric furnaces, and the like because of their small size, light weight, and low cost. However, since thyristor control is phase angle control, higher-order harmonics are generated, which may leak to a commercial power supply line and adversely affect other electronic devices.

Further, as this kind of AC power regulator,
For example, the one described in JP-A-9-34564 is known. In the AC power regulator described in this document, two sets of AC switches including a first AC switch and a second AC switch are used, the first AC switch is provided between the input side and the output side, and the second AC switch is further provided. Is provided on the output side of the first AC switch and at a position where the output side is short-circuited.
Then, the first AC switch and the second AC switch are turned on and off alternately at a predetermined cycle. However, even when the first AC switch and the second AC switch are turned on and off alternately, both the AC switches are turned on, and the circuit may be short-circuited and short-circuit current may be generated. Therefore, an off period in which both the first AC switch and the second AC switch are turned off is provided to prevent a short circuit of the circuit.

[0006]

However, in the AC power regulator as described in the above document, when a transistor is used as the AC switch, for example, the control of the AC switch is delayed due to the accumulation time of the transistor.
In addition, since the accumulation time greatly changes depending on the ambient temperature of the transistor and the magnitude of the collector current, it is very difficult to appropriately control the AC switch and appropriately provide the above-described off period, and it is difficult to put the battery into practical use. .

Further, a snubber circuit for absorbing a spike voltage is connected to each of the first AC switch and the second AC switch. However, if the off period is set to be longer than the accumulation time of the transistor. In this off period, an open state of the circuit occurs. As a result, a spike voltage is generated due to the reactance component of the circuit, the loss in the snubber circuit increases, and heat generation and burning are likely to occur. Therefore, when the first AC switch and the second AC switch are alternately turned on and off at a high frequency as in the prior art, the frequency of the open state of the circuit also becomes high, and the spike voltage is generated at a high frequency. As a result, the efficiency of the AC power regulator decreases.

An object of the present invention is to solve such a problem of the prior art, in which an AC switch for output control and an AC switch for circulation are respectively provided with a first switch, a second switch, and a second switch. In the first half cycle of the input AC power supply, the first switch is turned on / off at a high frequency of 10 kHz or more, and the third switch is turned on at a predetermined frequency higher than the frequency of the input AC power supply. The fourth switch is turned on and off at a timing substantially opposite to that of the first switch, and the fourth switch is kept in the on state.
In the remaining half cycle of the input AC power supply, the second switch is turned on / off at a high frequency of 10 kHz or more, and the fourth switch is turned on at a predetermined frequency higher than the frequency of the input AC power supply, at a timing substantially opposite to the second switch. And the third switch is kept on.

As a result, the spike voltage is generated at a high frequency and the loss increases when the circulating operation is performed at a high frequency as in the prior art. Only when it is turned on / off, an open state of the circuit occurs and a spike voltage is generated.
(Reflux operation will be described later.) Since the generation cycle of this spike voltage is the same as the cycle of the input AC power supply,
The loss is smaller than before, and a highly efficient AC power regulator can be realized. Further, even when the load connected to the output terminal is an inductive load, the AC power regulator of the present invention performs a stable operation without breaking the output waveform during the circulation operation.

[0010]

In order to achieve the above object, the present invention provides a pair of input terminals for connecting an input AC power supply, a pair of output terminals for connecting a load, a first switch and a second switch. And an AC switch for reflux configured by connecting a third switch and a fourth switch in series with each other, and one of the input terminals and the output terminal. Is connected to a common common line, the other of the input terminals is connected to one end of the output control AC switch, and the other of the output terminals is the other end of the output control AC switch and the return AC switch. The other end of the return AC switch is connected to the common line, the AC power regulator to convert the input AC power to an arbitrary voltage, current, or power and output the power, In the first half cycle of the input AC power supply, the first switch is turned on / off at a predetermined frequency higher than the frequency of the input AC power supply by a drive signal from a drive circuit, and the third switch is connected to the input AC power supply. At a predetermined frequency higher than the frequency, the first switch is turned on and off at a timing substantially opposite to that of the first switch, the fourth switch is kept on, while the other half cycle of the input AC power supply, the other half of the cycle from the drive circuit According to the drive signal, the second switch is turned on and off at a predetermined frequency higher than the frequency of the input AC power supply, and the fourth switch is at a predetermined frequency higher than the frequency of the input AC power supply and at a timing substantially opposite to that of the second switch. And the third switch is kept on.

In the present invention, each of the first to fourth switches is composed of a semiconductor element, and a diode is connected between controlled terminals of the semiconductor element in a direction opposite to a conduction direction thereof. , And the first switch and the second switch, and the third switch and the fourth switch are connected to each other at the same-polarity controlled terminals of the semiconductor elements.

According to this configuration, the circulating operation of the circulating AC switch of the present invention is performed at the same frequency as the frequency of the input AC power supply. The generation of a spike voltage is very small as compared with a regulator, and a highly efficient AC power regulator can be realized. Further, even when the load connected to the output terminal is an inductive load, the AC power regulator operates stably without breaking the output waveform during the circulation operation.

Further, the driving circuit of the present invention receives a high-frequency signal from a high-frequency signal generator and a detection signal from a flip-flop for detecting the polarity of an input AC power supply,
The driving signal is output to the output control AC switch and the return AC switch.

Further, the high-frequency signal generator of the present invention comprises:
A transmitter that generates a sawtooth wave, a reference voltage generator that generates an arbitrary reference voltage, and compares the sawtooth wave from the transmitter and the reference voltage from the reference voltage generator to generate the high-frequency signal. And a comparator for outputting to the driving circuit.

According to this configuration, the output control AC switch and the circulating AC switch can be controlled with a relatively simple control circuit.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. 1 is a circuit configuration diagram of an AC power regulator according to the present invention, FIG. 2 is a timing chart of a high-frequency signal from a high-frequency signal generator, FIG. 3 is a timing chart of first to fourth switches, and FIG. FIG. 5 is a circuit diagram for explaining the operation of the AC power regulator according to the present invention, and FIG. 5 is an operation timing diagram of the first switch and the third switch.

First, a circuit configuration of an AC power regulator according to the present invention will be described with reference to FIG. The AC power regulator includes input terminals 1 a and 1 b for connecting an input AC power supply P, and a load 2.
Output switches 3a and 3b, an output control AC switch 4 and a reflux AC switch 5, and an input filter 6
And an output filter 7. The input terminal 1b and the output terminal 3b are connected by a common common line Y. The input terminal 1a is connected to one end of the output control AC switch 4 via the input filter 6, and the output terminal 3a is connected to the other end of the output control AC switch 4 and the circulating AC switch via the output filter 7. It is connected to one end of the switch 5. Furthermore, the other end of the circulation AC switch 5 is connected to the common line Y. A drive circuit 13 is connected to each of the output control AC switch 4 and the circulation AC switch 5. Further, the driving circuit 1
3, a high-frequency signal generator 8 including a transmitter 9, a reference voltage generator 10, and a comparator 11, and a flip-flop 12 are connected.

The input AC power supply P has a commercial frequency (50 Hz).
Or 60 Hz) AC voltage (for example, single-phase 200 V), which is input between the input terminals 1a and 1b. The load 2 includes a resistor R and a reactor L3, and is connected to output terminals 3a and 3b.

The output control AC switch 4 comprises a first switch Q1, a second switch Q2 comprising transistors, and two diodes D1, D2. A diode D1 is connected between the collector and the emitter of the first switch Q1.
Are connected in the direction opposite to the conduction direction. Similarly, a diode D2 is connected between the collector and the emitter of the second switch Q2 in a direction opposite to the conduction direction. Then, the respective emitters of the first switch Q1 and the second switch Q2 are connected to each other to form an AC switch 4 for output control.

The circulating AC switch 5 comprises a third switch Q3 and a fourth switch Q4 each composed of a transistor, and two diodes D3 and D4. A diode D3 is connected between the collector and the emitter of the third switch Q3 in a direction opposite to the conduction direction. Similarly, a diode D4 is connected between the collector and the emitter of the fourth switch Q4 in a direction opposite to the conduction direction. Then, the respective emitters of the third switch Q3 and the fourth switch Q4 are connected to each other to form the circulating AC switch 5.

The high-frequency signal generator 8 generates a high-frequency sawtooth wave 14.
, A reference voltage generator 10 for generating an arbitrary reference voltage 15, a saw-tooth wave 14 from the transmitter 9 and a reference voltage 15 from the reference voltage generator 10, 1 that outputs a high-frequency signal of about 20 kHz to
And 1.

The flip-flop 12 is connected between one end on the input side of the output control AC switch 4 and the common line Y, detects the polarity of the input AC voltage, and outputs a detection signal to the drive circuit 13. .

The drive circuit 13 receives the high-frequency signal from the high-frequency signal generator 8 and the detection signal from the flip-flop 12, and receives a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch. A drive signal is output to each of Q4.

The input filter 6 includes a reactor L1 and a capacitor C1. The output filter 7
Is composed of a reactor L2 and a capacitor C2. With the input filter 6 and the output filter 7,
The pulsation of the input AC voltage and the output AC voltage can be reduced, and high frequency components can be removed.

Next, the circuit operation of the AC power regulator will be described with reference to FIGS. 60 as input AC power supply
The operation in the case where a 60 Hz single-phase 100 V output AC voltage is supplied to the output terminals 3 a and 3 b using a single-phase 200 V input AC voltage V will be described.

First, in a period T2 (see FIG. 3) which is the first positive half cycle of the input AC voltage V, a high-frequency sawtooth wave 14 of about 20 kHz generated by the transmitter 9 and a reference voltage generator 10 The comparator 11 makes a comparison with the reference voltage 15 adjusted to a predetermined value generated in the above. And saw wave 1
The on-time T1 (see FIG. 2), which is a period in a common region between the rising portion of the reference voltage 4 and the reference voltage 15, is set to a high level.
A high-frequency signal whose other periods are at low level is output from the high-frequency signal generator 8 to the drive circuit 13. When this high-frequency signal is output to the transistor, the transistor is kept on only during the on-time T1, and is kept off during the other periods. Further, the polarity of the input AC voltage V is detected by the flip-flop 12, and the detection signal is output to the drive circuit 13.

The drive circuit 13 receives the high-frequency signal from the high-frequency signal generator 8 and the detection signal from the flip-flop 12, and receives a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch. A drive signal is output to each of Q4. As a result, as shown in FIG. 3, the first switch Q1 repeatedly turns on and off at about 20 kHz,
The third switch Q3 repeats ON / OFF at a timing substantially opposite to that of the first switch Q1 and at about 20 kHz. At this time, in order to eliminate a period in which the first switch Q1 and the third switch Q3 are simultaneously turned on, an off period T4 in which both the first switch Q1 and the third switch Q3 are turned off (FIG. 5).
Reference). In addition, the second switch Q2 and the fourth switch Q4 maintain the ON state during the period T2.

In the period T2 shown in FIG. 3, the first switch Q
When 1 is turned on, the circuit current becomes a solid arrow 16 (see FIG. 4).
, The current flows through the first switch Q1 and the diode D2, and the circuit current is supplied to the load 2. Also, the first switch Q1
While the switch is on, the third switch Q3 keeps the off state. When the first switch Q1 is turned off, the circuit current flows through the fourth switch Q4 and the diode D3 as indicated by a solid arrow 17 (see FIG. 4), and the energy stored in the reactors L2 and L3 is released. (Hereinafter, this is referred to as a recirculation operation.) Further, while the first switch Q1 is off, the third switch Q3 keeps on, and when the load 2 is an inductive load, a broken arrow 19 (FIG. Circuit current flows as shown in FIG. During the period T2, the first switch Q
The first and third switches Q3 are at substantially opposite timings to each other,
The above operation is repeated at a high frequency of about 20 kHz.

Next, in a period T3 (see FIG. 3) which is a negative half cycle of the input AC voltage V, similarly to the period T2,
The drive circuit 13 receives the high-frequency signal from the high-frequency signal generator 8 and the detection signal from the flip-flop 12,
First switch Q1, second switch Q2, third switch Q
A drive signal is output to each of the third and fourth switches Q4. As a result, the second switch Q2 repeats on / off at about 20 kHz, and the fourth switch Q4 repeats on / off at about 20 kHz at a timing substantially opposite to that of the second switch Q2. At this time, as in the case of the period T2, in order to eliminate a period in which the second switch Q2 and the fourth switch Q4 are simultaneously turned on, an off period in which both the second switch Q2 and the fourth switch Q4 are turned off is provided. In addition, the first switch Q1 and the third switch Q3 maintain the ON state during the period T2.

In a period T3 shown in FIG. 3, the second switch Q
When the switch 2 is turned on, the circuit current is changed to a dashed arrow 18 (see FIG. 4).
, The current flows through the second switch Q2 and the diode D1, and the circuit current is supplied to the load 2. Also, the second switch Q2
While the switch is on, the fourth switch Q4 keeps the off state. When the second switch Q2 is turned off, the circuit current flows through the third switch Q3 and the diode D4 as indicated by a dashed arrow 19 (see FIG. 4), and the energy stored in the reactors L2 and L3 is released. Further, while the second switch Q2 is off, the fourth switch Q4 holds the on state, and when the load 2 is an inductive load, the circuit current is reduced as indicated by a solid arrow 17 (see FIG. 4). Flows. Period T3
During this time, the second switch Q2 and the fourth switch Q4 repeat the above operation at substantially the opposite timing and at a high frequency of about 20 kHz.

As described above, in the period T2, the first switch Q1 repeats on / off at a high frequency of about 20 kHz, and the third switch Q3 operates at a timing substantially opposite to that of the first switch Q1 and at a high frequency of about 20 kHz. Repeat on / off. Further, the second switch Q2 and the fourth switch Q
4 hold the ON state. On the other hand, in the period T3, the second switch Q2 is turned on at a high frequency of about 20 kHz.
The fourth switch Q4 is repeatedly turned off.
The on / off operation is repeated at a timing substantially opposite to that at 2 and at a high frequency of about 20 kHz. Further, both the first switch Q1 and the third switch Q3 maintain the ON state. Further, the period T2 and the period T3 are alternately repeated at a cycle of 60 Hz. With the above operation, the load 2 is supplied with an output AC voltage of 60 Hz, single-phase 100 V.

As a result, for example, in the period T2, when the first switch Q1 is turned on / off at a high frequency, the operation immediately returns to the recirculation operation when the first switch Q1 is turned off. No spike voltage is generated in a snubber circuit (not shown) connected to the fourth switch Q4. However, when shifting from the period T2 to the period T3, an open state of the circuit occurs, and a spike voltage is generated. That is, the cycle of the input AC voltage V (60H
A spike voltage is generated at z).

The case where the input AC voltage of single-phase 200V is converted to the output AC voltage of single-phase 100V has been described above, but by changing the magnitude of the reference voltage 15,
The output AC voltage can be adjusted arbitrarily. By changing the magnitude of the reference voltage 15, FIG.
, The ON time when the first switch Q1 to the fourth switch Q4 are turned on and off at a high frequency can be varied, and the magnitude of the output AC voltage can be adjusted. The output AC voltage increases in proportion to the ON time T1. Therefore, the output AC voltage can be controlled by the high-frequency signal from the high-frequency signal generator 8, and the output AC voltage is opposite to one end on the output side of the output control AC switch 4 and the common line Y of the circulation AC switch 5. It is determined by the average value of the voltage at each point of one end of the output filter 7 and one end of the input side of the output filter 7. As a result, by continuously varying the magnitude of the reference voltage 15, the magnitude of the output AC voltage also changes from near zero voltage to near the input AC voltage,
It can be continuously varied from% to 100%.

Although the embodiment of the present invention has been described above, the present invention can be implemented in other embodiments. For example,
MOSFETs may be used as the semiconductor elements forming the first to fourth switches. Although the present invention has been described in various ways, the present invention can be embodied in variously modified, modified, and modified forms based on the knowledge of those skilled in the art without departing from the spirit thereof.

[0035]

According to the AC power regulator of the present invention, the circulating operation of the circulating AC switch of the present invention is performed at the same frequency (50 Hz or 60 Hz) as the frequency of the input AC voltage. The generation of the spike voltage is extremely reduced as compared with the AC power regulator that performs the circulating operation. Therefore, the loss in the snubber circuit is reduced, and a highly efficient AC power regulator can be realized. Further, even when the load connected to the output terminal is an inductive load, the AC power regulator operates stably without breaking the output waveform during the circulation operation. Further, the output control AC switch and the circulation AC switch can be controlled with a relatively simple control circuit.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an AC power regulator according to the present invention.

FIG. 2 is a timing chart of a high-frequency signal according to the present invention.

FIG. 3 is a timing chart of first to fourth switches of the present invention.

FIG. 4 is a circuit diagram for explaining the operation of the AC power regulator of FIG. 1;

FIG. 5 is an operation timing chart of a first switch and a third switch.

[Explanation of symbols]

P input AC power supply 1a, 1b input terminal 2 Load 3a, 3b output terminal 4 AC switch for output control 5 AC switch for circulation 6 Input filter 7 Output filter 8 High frequency signal generator 9 transmitter 10 Reference voltage generator 11 Comparator 12 flip-flops 13 Drive circuit

Claims (4)

[Claims] An output control AC switch configured by connecting a pair of input terminals for connecting an input AC power supply, a pair of output terminals for connecting a load, and a first switch and a second switch in series, A return AC switch configured by connecting a third switch and a fourth switch in series, one of the input terminals and one of the output terminals are connected to a common common line, and the other of the input terminals Is connected to one end of the output control AC switch, the other of the output terminals is connected to the other end of the output control AC switch and one end of the return AC switch, and the other end of the return AC switch is In an AC power regulator connected to a common line and converting the input AC power to an arbitrary voltage, current, or power and outputting the voltage, a driving circuit from a driving circuit is provided in the first half cycle of the input AC power. The first switch is turned on and off at a predetermined frequency higher than the frequency of the input AC power supply, and the third switch is at a predetermined frequency higher than the frequency of the input AC power supply and has a timing substantially opposite to that of the first switch. And the fourth switch is kept on, while in the other half cycle of the input AC power, the second switch is turned on by the drive signal from the drive circuit. The fourth switch is turned on / off at a higher predetermined frequency, the fourth switch is turned on / off at a timing substantially opposite to that of the second switch at a predetermined frequency higher than the frequency of the input AC power supply, and the third switch is kept on. AC power regulator characterized by making it. 2. The semiconductor device according to claim 1, wherein each of the first to fourth switches includes a semiconductor element, and a diode is connected between controlled terminals of the semiconductor element in a direction opposite to a conduction direction thereof. 2. The AC power adjustment according to claim 1, wherein the switch and the second switch and the third switch and the fourth switch are connected to control terminals having the same polarity of semiconductor terminals. vessel. 3. The drive circuit according to claim 1, wherein the drive circuit receives a high-frequency signal from a high-frequency signal generator and a detection signal from a flip-flop for detecting the polarity of an input AC power supply, and outputs the output control AC switch and the return AC. The AC power regulator according to claim 1, wherein the drive signal is output to a switch. 4. The high-frequency signal generator includes a transmitter that generates a sawtooth wave, a reference voltage generator that generates an arbitrary reference voltage, and a sawtooth wave from the transmitter and a signal from the reference voltage generator. 4. The AC power regulator according to claim 1, further comprising: a comparator that compares the reference voltage with the reference voltage and outputs the high-frequency signal to the drive circuit. 5.