JP2003023775A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components of a power converter to realize cost reduction and improve efficiency. SOLUTION: A bidirectional switching circuit, comprising a series circuit of diodes D1 and D2, a series circuit of a semiconductor switches Q1 and Q2, and a capacitor C1 which are connected in parallel with each other, is combined with a transformer Tr1, a reactor L1 and L2, a capacitor C2, etc. An output voltage Vout is controlled by the control of the switching frequencies of the semiconductor switches Q1 and Q2. The DC voltage Ed of the capacitor C1 of the bidirectional switching circuit is controlled by the control of the duties of the semiconductor switches Q1 and Q2. Using such a constitution, the number of components can be reduced farther in comparison with a conventional constitution.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a power converter for converting AC power into DC power.

[0002]

2. Description of the Related Art FIG. 16 shows a conventional example of a power conversion device formed by combining a diode rectifier circuit, a booster type chopper circuit and a current resonance type DC / DC converter.
This is to rectify an AC input by a diode rectifier circuit composed of diodes D1, D2, D7, D8, and boost a DC voltage Ed to a desired DC voltage by a boost chopper circuit composed of a reactor L1, a switch Q4, a diode D9 and a capacitor C1. Switch Q2 (diode D
3), switch Q3 (diode D4), transformer Tr
1, capacitor C2, reactor L2, diode D
5, a desired output DC voltage Vout is obtained by a current resonance type DC / DC converter including a diode D6 and a capacitor C3.

The control of Q1 to Q4 is performed as follows with the configuration shown in the drawing. The deviation between the DC voltage command value Ed ^* and the DC voltage detection value Ed is input to the controller R2, the triangular wave generated from the triangular wave generation circuit G2 and the output from the controller R2 are compared by the comparator H2, and the gate is driven. Circuit GD
The switch Q4 is driven by U so that the DC voltage becomes a desired voltage. Further, the deviation between the output voltage command value Vout ^* and the output voltage detection value Vout is input to the controller R1, and the frequency of the triangular wave generated by the triangular wave generation circuit G1 according to the output of the controller R1 is changed. Further, in general, a comparator H1 compares a reference signal that is half the peak value of the triangular wave and the triangular wave generated from the triangular wave generation circuit G1.
Then, the gate drive circuit GDU alternately turns on and off the on / off ratios of the switches Q1 and Q2 at a constant ratio of 0.5: 0.5 so that the output voltage Vout becomes a desired voltage.

The circuit input current waveform in this case is in the form of a triangular pulse train as shown in FIG. 17, and the magnitude of each triangular wave is approximately proportional to the instantaneous voltage of the input voltage. By inserting a high frequency filter circuit composed of a reactor L and a capacitor C between the AC power supply VS and the power supply circuit as shown in FIG. 18 in the input section, the power supply current becomes a continuous sinusoidal current waveform, and a high It will be input power factor.

[0005]

However, since the number of parts is large in the above structure, the device is not only expensive, but also the number of semiconductors used and the number of pass elements in the current path are large. There is a problem that the efficiency of the device decreases. Therefore, an object of the present invention is to reduce the cost by reducing the number of parts and to improve the efficiency of the device.

[0006]

In order to solve such a problem, according to the invention of claim 1, in a power converter for converting AC power from a single-phase AC power supply into DC power, a self-arc-extinguishing type semiconductor element is provided. And a diode connected in antiparallel to each other, a series circuit of a first switch and a second switch, a series circuit of a first diode and a second diode, and a first capacitor in parallel with each other, and The connection point with the two diodes is connected to one terminal of the AC power supply via the first reactor, the other terminal of the AC power supply is connected to the first switch,
At the connection point of the second switch, a series circuit of the first winding of the transformer, the second reactor, and the second capacitor in parallel with the first switch or the second switch, one of the second winding of the transformer. Is connected to one terminal of the third capacitor via the third diode, and the other terminal of the second winding of the transformer is connected to the other terminal of the third capacitor and one of the third winding of the transformer. And the other terminal of the third winding of the transformer is connected to one terminal of the third capacitor through the fourth diode.

According to a second aspect of the present invention, in a power converter for converting AC power from a single-phase AC power supply into DC power,
A series circuit of a first switch and a second switch in which a self-extinguishing type semiconductor device and a diode are connected in antiparallel;
A capacitor in parallel with each other, a series circuit of a first diode and a second diode, and a series circuit of a third diode and a fourth diode in parallel with the first switch or the second switch; The connection point with two diodes is connected to one terminal of the AC power supply via the first reactor, and the other terminal of the AC power supply is connected to the third diode and the fourth diode.
At the connection point with the diode, a series circuit of the first winding, the second reactor, and the second capacitor of the transformer is connected in parallel with the first switch or the second switch, and one of the second windings of the transformer is connected. The terminal is connected to one terminal of the third capacitor through the fifth diode, and the other terminal of the second winding of the transformer is connected to the other terminal of the third capacitor and one of the third winding of the transformer. It is characterized in that the other terminal of the third winding of the transformer is connected to one terminal of the third capacitor via a sixth diode.

According to a third aspect of the present invention, in a power conversion device for converting AC power from a single-phase AC power supply into DC power, a first switch formed by connecting a self-arc-extinguishing type semiconductor element and a diode in antiparallel. A series circuit of the second switch and the third switch, and a first capacitor in parallel with each other, a series circuit of the first diode and the second diode, a series circuit of the first switch and the second switch or the second switch And a third switch in parallel with each other, the connection point between the first diode and the second diode is connected to one terminal of the AC power supply via the first reactor, and the other terminal of the AC power supply is connected to the first switch. To the second switch, or
A series circuit of the first winding of the transformer, a second reactor, and a second capacitor at a connection point between the second switch and the third switch, a series circuit of the first switch and the second switch,
Alternatively, in parallel with the series circuit of the second switch and the third switch, one terminal of the second winding of the transformer is connected to one terminal of the third capacitor through the third diode and the first terminal of the transformer is connected. The other terminal of the two windings is connected to the other terminal of the third capacitor and one terminal of the third winding of the transformer, and the other terminal of the third winding of the transformer is connected to the other terminal of the third winding via a fourth diode. It is characterized in that it is connected to one terminal of the third capacitor, respectively.

In the invention according to any one of claims 1 to 3, the switch is turned on and off at a constant ratio while changing the on and off periods so that the voltage of the third capacitor becomes a set value. Can be controlled (claim 4
Of the invention), or by turning the switch on and off while changing the on and off periods and the on and off ratios, and controlling the voltage of the third capacitor to the set value (claim 5). Invention), or by controlling the voltage of the first capacitor to a set value by changing the ON / OFF ratio of the switch, and changing the ON / OFF cycle of the switch to control the voltage of the third capacitor. The voltage can be controlled so as to reach the set value (the invention of claim 6).

[0010]

1 is a block diagram showing a first embodiment of the present invention. As shown in the figure, semiconductor switches Q1 and Q2 having a self-extinguishing function (here, the semiconductor switches are metal oxide film type field effect transistor MOSFETs).
However, in that case, the diodes D3 and D4 connected in parallel with the switch may be parasitic diodes in the MOSFET. Further, when the insulated gate bipolar transistor IGBT is used as the semiconductor switch, it is necessary to connect the diodes D3 and D4 in parallel with the switch. ) Is connected in parallel with the series circuit of the capacitor C1 and the diodes D1 and D2, and the series connection point of the diodes D1 and D2 is connected to one terminal of the AC power supply VS via the reactor L1 and a switch. Q1
And the series connection point of Q2 are connected to the other terminals of the AC power supply VS.

Further, a series circuit of the reactor L2, the first winding N1 of the transformer Tr1 and the capacitor C2 is connected in parallel with the switch Q2. If the reactor L2 can be replaced by the leakage inductance of the transformer Tr1, this can be omitted. Further, one terminal of the second winding N2 of the transformer Tr1 is connected to one terminal of the capacitor C3 via the diode D5 and the winding N2.
The other terminal of the capacitor C3 to the other terminal of the third winding N3 of the transformer Tr1, and the other terminal of the third winding N3 of the transformer Tr1 to the diode D.
It is connected to one terminal of the capacitor C3 via 6.

When the polarity of the AC power supply in the circuit of FIG. 1 is positive (the direction of the arrow in FIG. 1 is positive), FIG.
Description will also be made with reference to 15. FIG. 14 shows the case of modes 1 and 2, and FIG. 15 shows the case of modes 3 and 4. When the mode 1 switch Q1 is turned on, the power supply is short-circuited via the reactor L1, and a current flows in the path of AC power supply VS → reactor L1 → diode D1 → switch Q1 → AC power supply VS, and energy is accumulated in the reactor L1. At the same time, capacitor C1 → switch Q1 → reactor L
2 → first winding N1 of transformer Tr1 → capacitor C2 →
Current flows in the path of the capacitor C1, and during this period, current flows from the second winding N2 of the transformer Tr1 to the load RL via the diode D5. The current flowing through the capacitor C2 can be calculated by ignoring the leakage inductance of the transformer.
Resonant operation is performed by the reactor L2 and the capacitor C2.

When the mode 2 switch Q2 is turned off, the energy stored in the reactor L1 is released in the path of the AC power supply VS → reactor L1 → diode D1 → capacitor C1 → diode D4 → AC power supply VS, and the energy is stored in the capacitor C1. Accumulated. Further, during this period, current continues to flow in the path of the reactor L2 → the first winding N1 of the transformer Tr1 → the capacitor C2 → the diode D4, and the load RL has the second winding N2 of the transformer Tr1 → the diode D5 → the capacitor C3 → Load RL in the path of the second winding N2 of the transformer Tr1
Current flows through. When the switch Q2 is turned on while the current is flowing through the diode D4, the switch Q2 is turned on at zero voltage and zero current.

Mode 3 The current flowing in the capacitor C2 continues to resonate in the reactor L2 and the capacitor C2, and the polarity of the current flowing in the capacitor C2 is opposite to that in modes 1 and 2, and the capacitor C2 → transformer Tr1 First winding N1 →
Current flows through the path of reactor L2 → switch Q2 → capacitor C2, and current flows through load RL through the path of third winding N3 of transformer Tr1 → diode D6 → capacitor C3 → third winding N3 of transformer Tr1.

Mode 4 When the switch Q2 is turned off, the current flowing through the capacitor C2 is changed from the capacitor C2 to the first winding N1 of the transformer Tr1 to the reactor L2 to the diode D3 to the capacitor C.
1 → current flows in the path of the capacitor C2, and during this period, the third winding N3 of the transformer Tr1 → diode D6
→ Capacitor C3 → Current flows through the load RL in the path of the third winding N3 of the transformer Tr1. When the switch Q1 is turned on while the current is flowing through the diode D3, the switch Q1 is turned on at zero voltage and zero current. If the power supply polarity is negative, switch Q2
When is turned on, the AC power supply VS is short-circuited via the reactor L1, and the AC power supply VS → switch Q2 → diode D2.
→ Reactor L1 → Current flows in the path of AC power supply VS,
The description is omitted because it is the same as the case where the power source polarity is positive except that energy is stored in the reactor L1.

In controlling the switches Q1 and Q2, the output voltage command value Vout ^* and the output voltage detection value Vou are shown in FIG.
The deviation from t is input to the controller R1, and the frequency of the triangular wave generated by the triangular wave generation circuit G is changed according to the output of the controller R1. Further, the comparator H1 compares the reference signal that is half the peak value of the triangular wave with the triangular wave generated from the triangular wave generation circuit G, and the gate drive circuit GDU drives the switches Q1 and Q2. At this time, switch Q1
By alternately turning on and off the ON and OFF ratios of Q2 and Q2 at a constant ratio of 0.5: 0.5 and changing the switching frequency according to the deviation between the output voltage command value Vout ^* and the output voltage detection value Vout. , So that the output voltage Vout becomes a desired voltage. As shown in FIG. 17, the input current waveform becomes a triangular pulse train substantially proportional to the instantaneous voltage of the power supply voltage when the switches Q1 and Q2 are turned on and off. Therefore, for example, the reactor shown in FIG. As in the case of FIG. 16, the input current can be made a continuous sinusoidal current by inserting a filter made of a capacitor between the AC power supply and the power conversion device.

FIG. 2 shows a modification of FIG. Reactor L
1 and the series circuit of the first winding N1 of the transformer Tr1 and the capacitor C2 are connected in parallel with the switch Q2 in FIG. 1, but the basic function is different only in that they are connected in parallel with the switch Q1. Since the operation is the same as in the case of FIG. 1, the description is omitted.

FIG. 3 is a block diagram showing another modification of FIG. This is different from that shown in FIG. 1 in voltage detectors K2, K.
3, a regulator R2, a polarity discriminating circuit DP, an on / off ratio inverting circuit IO and the like are added. That is, the deviation between the DC voltage command value Ed ^* and the DC voltage detection value Ed is fed to the regulator R2, the output of the regulator R2 is fed to the comparator H1, and the comparator H1.
To the on / off ratio inversion circuit IO.
Further, the polarity of the AC power supply VS is determined by the voltage detector K3 and the polarity determination circuit DP, and the output thereof is input to the on / off ratio inverting circuit IO. The output of the on / off ratio inversion circuit IO is input to the gate drive circuit GDU and drives the switches Q1 and Q2.

With the configuration shown in FIG. 3, the on / off ratios of the switches Q1 and Q2 are changed according to the deviation between the DC voltage command value Ed ^* and the DC voltage detection value Ed, and the output voltage command is changed. Value Vout ^* and output voltage detection value Vou
The switching frequency is changed according to the deviation from t, and the switches Q1 and Q2 are turned on according to the polarity of the power supply.
By inverting the off ratio, the DC voltage Ed and the output voltage V
Out can be controlled to have a desired value.
It is needless to say that such control can be applied to the main circuit shown in FIG.

FIG. 4 is a block diagram showing a second embodiment of the present invention. This is because the series circuit of the diodes D1 and D2, the series circuit of the diodes D7 and D8, and the switch Q2 are connected in parallel, and the connection point of the diodes D1 and D2 is connected to one of the AC power supply VS via the reactor L1 and the diode D7. It is characterized in that the connection point between D8 and D8 is connected to the other side of the AC power supply VS. The on / off ratios of the switches Q1 and Q2 are also arbitrary here. The reactor L1
Is the connection point between the diodes D1 and D7 and the switches Q1 and Q
It may be connected between the connection point with the node 2, or between the connection point between the diodes D2 and D8 and the connection point between the capacitor C1 and the switch Q2. In the operation of FIG. 4, regardless of whether the polarity of the AC power supply VS is positive or negative, when the switch Q2 is turned on, the power supply is short-circuited via the reactor L1 and the reactor L
1 is different from the case of FIG. 1 in that energy is stored, and the other points are the same as those in FIG.

FIG. 5 is a block diagram showing a first modification of FIG. First winding N1 of reactor L2 and transformer Tr1
And a capacitor C2 in series circuit, switch Q in FIG.
2 is connected in parallel, but here, the basic function and operation are shown in FIG.
The description is omitted because it is the same as the case.

FIG. 6 is a block diagram showing a second modification of FIG. In FIG. 4, the switch Q2 is connected in parallel to each of the series circuit of the diodes D1 and D2 and the series circuit of the diodes D7 and D8, but the feature here is that the switch Q1 is connected in parallel. At this time, the reactor L1
May be connected between the connection point between the diodes D1 and D7 and the connection point between the capacitor C1 and the switch Q1, or between the connection point between the diodes D2 and D8 and the connection point between the switches Q1 and Q2. The operation in this case is the same as the case of FIG. 4 in that the power source is short-circuited via the reactor L1 when the switch Q1 is turned on, and energy is stored in the reactor L1.

FIG. 7 is a block diagram showing a third modification of FIG. In FIG. 4, the switch Q2 is connected in parallel to each of the series circuit of the diodes D1 and D2 and the series circuit of the diodes D7 and D8, but here, the switch Q1 is connected in parallel, and the reactor L2 and the transformer Tr.
Although the series circuit of the first first winding N1 and the capacitor C2 is connected in parallel with the switch Q2 in FIG. 4, it is characterized in that it is connected in parallel with the switch Q1. The reactor L1 may be connected between the connection point between the diodes D1 and D7 and the connection point between the capacitor C1 and the switch Q1, or between the connection point between the diodes D2 and D8 and the connection point between the switches Q1 and Q2. good.

FIG. 8 is a block diagram showing a fourth modification of FIG. This is different from the voltage detector K2 shown in FIG.
DC voltage Ed is detected with and this and DC voltage command value Ed ^*
The difference between and is input to the controller R2, the triangular wave output from the triangular wave generator G is compared with the output from the controller R2 by the comparator H1, and the switches Q1 and Q2 are driven. By doing so, the switches Q1 and Q2 are switched according to the deviation between the DC voltage command value Ed ^* and the DC voltage detection value Ed.
Of the DC voltage Ed and the output voltage Vout by changing the switching frequency according to the on / off ratio of the output voltage command value Vout ^* and the deviation between the output voltage command value Vout ^* and the output voltage detection value Vout.
Out is controlled so as to have a desired value. Since the operation of the main circuit is the same as that in the case of FIG. 4, description thereof will be omitted. Further, it goes without saying that such control can be similarly applied to the cases of FIGS. 5, 6 and 7.

FIG. 9 is a block diagram showing the third embodiment of the present invention. This is because the series circuit of the switches Q1, Q2 and Q3 is parallel to the capacitor C1, the series circuit of the switches Q2 and Q3 is parallel to the series circuit of the diodes D1 and D2, and the connection point of the diodes D1 and D2 is the reactor. L1
And a series circuit of the reactor L2, the first winding N1 of the transformer Tr1, and the capacitor C2 are connected in parallel to the series circuit of the switches Q2 and Q3, respectively, at a connection point between the switches Q2 and Q3 via the AC power supply VS. At the same time, the switches Q2 and Q3 are turned on and off at the same time and alternately with the switch Q1, and the reference signal of the comparator H1 is set arbitrarily.

In the configuration of FIG. 9, when the power source polarity is positive (the direction of the arrow of the power source is positive), the switch Q
When Q2 and Q3 turn on, AC power supply VS → reactor L
A current flows in the path of 1 → diode D1 → switch Q2 → AC power supply VS, and stores energy in the reactor L1. When the power supply polarity is negative, switches Q2 and Q3
When is turned on, a current flows in the path of AC power supply VS → switch Q3 → diode D2 → reactor L1 → AC power supply VS, and energy is stored in reactor L1. Also, the switch Q1 and the diode D3 are turned off, and the switch Q
The current path when 2, 2 and Q3 are on is reactor L2 → first winding N1 of transformer Tr1 → capacitor C2 → diode D7 → diode D4 → reactor L2, or
Reactor L2 → switch Q2 → switch Q3 → capacitor C2 → first winding N1 of transformer Tr1 → reactor L2 and passes through two semiconductor switches. Others are the same as in the case of FIG. 1, and the description thereof will be omitted.

FIG. 10 shows a first modification of FIG. As is clear from the figure, the reactor L2 and the transformer Tr
Although the series circuit of the first winding N1 of No. 1 and the capacitor C2 is connected in parallel with the switches Q2 and Q3 in FIG. 9, it is characterized in that it is connected in parallel with the switch Q1. In this case, the current path when the switch Q1 and the diode D3 are off and the switches Q2 and Q3 are on is the capacitor C1 →
Reactor L2 → first winding N1 of transformer Tr1 → capacitor C2 → switch Q2 → switch Q3 → capacitor C1 or capacitor C1 → diode D7 → diode D4 → capacitor C2 → first winding N1 of transformer Tr1 → reactor L2 → It becomes the capacitor C1 and passes through the two semiconductor switches. Other basic functions,
The operation is the same as in the case of FIG.

FIG. 11 shows a second modification of FIG. The point that the series circuit of the switches Q1, Q2, Q3 is connected in parallel with the capacitor C1 is the same as in FIG. 9, but the series circuit of the switches Q1, Q2 is connected in parallel with the series circuit of the diodes D1, D2, and the diode D1 is connected. And D2 are connected to the connection point between the reactor L1 and the switches Q1 and Q2 via the AC power supply VS, and the series circuit of the reactor L2, the first winding N1 of the transformer Tr1 and the capacitor C2 is connected in parallel to the switch Q3. They are different in that they are connected to each other and that the switches Q2 and Q3 are turned on and off at the same time and alternately with the switch Q1.

In the configuration of FIG. 11, when the power source polarity is positive (the direction of the arrow of the power source is positive), the AC power source VS → reactor L1 → diode D1 → when the switches Q1 and Q2 are turned on. A current flows through the path from the switch Q1 to the AC power supply VS, and energy is stored in the reactor L1. When the power supply polarity is negative, the switches Q1, Q
When 2 is turned on, a current flows through the path of AC power supply VS → switch Q2 → diode D2 → reactor L1 → AC power supply VS, and energy is stored in reactor L1. Further, the switch Q3 and the diode D7 are turned off, and the switch Q
The current path when 1, 1 and Q2 are on is capacitor C1 → switch Q1 → switch Q2 → reactor L2 → first winding N1 of transformer Tr1 → capacitor C2 → capacitor C
1 or capacitor C1 → capacitor C2 → first winding N1 of transformer Tr1 → reactor L2 → diode D4 → diode D3 → capacitor C1 and passes through two semiconductor switches. Others are the same as in the case of FIG. 9, and thus description thereof will be omitted.

FIG. 12 shows a third modification of FIG. The point that the series circuit of the switches Q1, Q2, Q3 is connected in parallel with the capacitor C1 is the same as in FIG. 9, but the series circuit of the switches Q1, Q2 is connected in parallel with the series circuit of the diodes D1, D2, and the diode D1 is connected. And D2 are connected to the connection point between the reactor L1 and the switches Q1 and Q2 via the AC power supply VS, and the series circuit of the reactor L2, the first winding N1 of the transformer Tr1 and the capacitor C2 is connected to the switches Q1 and Q2.
It is different in that the switches Q1 and Q2 are connected in parallel to a series circuit of 2 and the switches Q1 and Q2 are simultaneously turned on and off alternately with the switch Q3.

In the configuration of FIG. 12, when the power supply polarity is positive (the direction of the arrow of the power supply is positive), the AC power supply VS → reactor L1 → diode D1 → when the switches Q1 and Q2 are turned on. A current flows through the path from the switch Q1 to the AC power supply VS, and energy is stored in the reactor L1. When the power supply polarity is negative, the switches Q1, Q
When 2 is turned on, a current flows through the path of AC power supply VS → switch Q2 → diode D2 → reactor L1 → AC power supply VS, and energy is stored in reactor L1. Further, the switch Q3 and the diode D7 are turned off, and the switch Q
The current path when 1 and Q2 are on is reactor L2 → first winding N1 of transformer Tr1 → capacitor C2 → diode D4 → diode D3 → reactor L2, or
Reactor L2 → switch Q1 → switch Q2 → capacitor C2 → first winding N1 of transformer Tr1 → reactor L2 and passes through two semiconductor switches. Others are the same as in the case of FIG. 9, and thus description thereof will be omitted.

FIG. 13 shows a fourth modification of FIG. This is different from that shown in FIG. 9 in that the voltage detector K2 detects the DC voltage Ed, and the deviation between this and the DC voltage command value Ed ^* is input to the controller R2 and output from the triangular wave generator G. The triangular wave is compared with the output from the regulator R2 by the comparator H1, and the switches Q1, Q2 and Q3 are driven. By doing so, the switches Q1 and Q2 are switched according to the deviation between the DC voltage command value Ed ^* and the DC voltage detection value Ed.
By changing the ON / OFF ratio of Q3 and Q3 and changing the switching frequency according to the deviation between the output voltage command value Vout ^* and the output voltage detection value Vout, the DC voltage Ed and the output voltage Vout can be changed to desired values. It is controlled so that Since the operation of the main circuit is the same as that in the case of FIG. 9, description thereof will be omitted. In addition, such control is shown in FIG.
Of course, the same can be applied to the cases of FIGS. 11 and 12.

[0033]

According to the present invention, it is possible to reduce the input high frequency current with a small number of parts and to control the DC intermediate voltage and the output voltage. Also,
Compared with the conventional example, since the number of semiconductor elements that pass current can be reduced, higher efficiency can be achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a first modification of FIG.

FIG. 3 is a configuration diagram showing a second modification of FIG.

FIG. 4 is a configuration diagram showing a second embodiment of the present invention.

5 is a configuration diagram showing a first modified example of FIG. 4. FIG.

6 is a configuration diagram showing a second modification of FIG.

7 is a configuration diagram showing a third modification example of FIG. 4. FIG.

FIG. 8 is a configuration diagram showing a fourth modification of FIG.

FIG. 9 is a configuration diagram showing a second embodiment of the present invention.

10 is a configuration diagram showing a first modification example of FIG. 9. FIG.

11 is a configuration diagram showing a second modification of FIG. 9. FIG.

12 is a configuration diagram showing a third modification example of FIG. 9. FIG.

FIG. 13 is a configuration diagram showing a fourth modified example of FIG. 9.

FIG. 14 is an explanatory diagram of modes 1 and 2.

FIG. 15 is an explanatory diagram of modes 3 and 4.

FIG. 16 is a configuration diagram showing a conventional example.

FIG. 17 is a waveform diagram showing the circuit input current of FIG.

FIG. 18 is a circuit diagram showing an example of a harmonic filter circuit.

[Explanation of symbols]

VS ... AC power supply, D1-D9 ... Diode, GDU ... Gate drive circuit, Ed ... DC voltage, C1-C3 ... Capacitor, Tr1 ... Transformer (transformer), N1-N3 ... Transformer winding, L1, L2 ... Reactor, Q1-Q4 ... switch element, RL ... load, R1, R2 ... regulator, G, G1,
G2 ... Triangular wave generator, K1, K2, K3 ... Voltage detector,
H1, H2 ... Comparator, DP ... Polarity discrimination circuit, IO ... On / off ratio inverting circuit.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masakazu Iwazu             1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa             Within Fuji Electric Co., Ltd. F-term (reference) 5H006 AA01 AA02 CA02 CA07 CA12                       CA13 CB02 CB08 CC01 CC02                       DA02 DA04 DB02 DB05 DC05                 5H730 AA02 AA14 AA18 AS01 BB24                       BB57 BB66 CC01 CC04 DD04                       DD12 DD13 EE03 EE07 FD01                       FF02 FG05

Claims (6)

[Claims] 1. A power conversion device for converting AC power from a single-phase AC power supply into DC power, wherein a self-extinguishing semiconductor element and a diode are connected in anti-parallel and a first switch and a second switch are connected in series. Circuit and first
A series circuit of a diode and a second diode, and a first capacitor are parallel to each other, and a connection point between the first diode and the second diode is connected to one terminal of an AC power supply via the first reactor and the other of the AC power supply. At the connection point between the first switch and the second switch, the first winding of the transformer and the second
A series circuit of a reactor and a second capacitor is connected in parallel with the first switch or the second switch, and the second circuit of the transformer is connected.
One terminal of the winding is connected to one terminal of the third capacitor via the third diode, and the other terminal of the second winding of the transformer is connected to the other terminal of the third capacitor and the third terminal of the transformer. A power converter, wherein one terminal of the winding is connected to the other terminal of the third winding of the transformer via a fourth diode to one terminal of the third capacitor. 2. A power converter for converting AC power from a single-phase AC power supply into DC power, wherein a self-extinguishing semiconductor element and a diode are connected in anti-parallel and a first switch and a second switch are connected in series. Circuit and first
A capacitor in parallel with each other, a series circuit of a first diode and a second diode, and a series circuit of a third diode and a fourth diode in parallel with the first switch or the second switch; The connection point with two diodes is connected to one terminal of the AC power supply via the first reactor, and the other terminal of the AC power supply is connected to the third diode and the fourth diode.
At the connection point with the diode, a series circuit of the first winding, the second reactor, and the second capacitor of the transformer is connected in parallel with the first switch or the second switch, and one of the second windings of the transformer is connected. The terminal is connected to one terminal of the third capacitor through the fifth diode, and the other terminal of the second winding of the transformer is connected to the other terminal of the third capacitor and one of the third winding of the transformer. A power converter, wherein the other terminal of the third winding of the transformer is connected to one terminal of the third capacitor via a sixth diode. 3. A power converter for converting AC power from a single-phase AC power supply into DC power, wherein a self-extinguishing semiconductor element and a diode are connected in antiparallel to each other. A series circuit of three switches and a first capacitor in parallel with each other, a series circuit of a first diode and a second diode, a series circuit of the first switch and the second switch, or the second switch and the third switch In parallel with the series circuit, the connection point between the first diode and the second diode is connected to one terminal of the AC power supply via the first reactor, and the other terminal of the AC power supply is connected to the first switch and the second switch. Connection point, or
A series circuit of the first winding of the transformer, a second reactor, and a second capacitor at a connection point between the second switch and the third switch, a series circuit of the first switch and the second switch,
Alternatively, in parallel with the series circuit of the second switch and the third switch, one terminal of the second winding of the transformer is connected to one terminal of the third capacitor through the third diode and the first terminal of the transformer is connected. The other terminal of the two windings is connected to the other terminal of the third capacitor and one terminal of the third winding of the transformer, and the other terminal of the third winding of the transformer is connected to the other terminal of the third winding via a fourth diode. A power converter characterized in that it is connected to one terminal of a third capacitor, respectively. 4. The switch is turned on / off at a constant ratio while changing the on / off cycle, and the voltage of the third capacitor is controlled to a set value. The power converter according to any one of 1. 5. The switch according to claim 1, wherein the switch is turned on / off while changing the on / off period and the on / off ratio, and the voltage of the third capacitor is controlled to a set value. 3. The power conversion device according to any one of 3. 6. The voltage of the first capacitor is controlled to a set value by changing the ON / OFF ratio of the switch, and the ON / OFF cycle of the third capacitor is changed by changing the ON / OFF cycle of the switch. The power converter according to any one of claims 1 to 3, wherein the voltage is controlled to be a set value.