JPH05211764A - Chopper circuit - Google Patents

Abstract

PURPOSE:To enable a chopper circuit to convert electric power in two ways by connecting an opposite-direction polarity-inverted chopper to a normal- direction polarity-inverted chopper and controlling a first and second DC switches. CONSTITUTION:When a load current is large, a semiconductor switching element (IGBT) 10 is controlled by means of a circuit composed of the IGBT 10 and a diode 20. When the IGBT 10 is turned on, an electric current (i1) starts to flow and energy is accumulated in a reactor 4. When the IGBT 10 is turned off, another electric current i2 starts to flow and the energy accumulated in the reactor 4 is discharged to a load 5. When the output voltage is to be dropped in a state where the load current hardly flows or when the power of the load is regenerated by means of a DC machine, another IGBT 11 is controlled by means of another circuit composed of the IGBT 11 and another diode 21. When the IGBT 11 is turned on, an electric current i4 starts to flow and energy is accumulated in the reactor 4. When the IGBT 11 is turned off, another electric current i3 starts to flow and the energy accumulated in the reactor 4 is discharged to a DC power source. As a result, regeneration takes place.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

FIELD OF THE INVENTION The present invention relates to a chopper circuit.

[0002]

2. Description of the Related Art A chopper circuit is a power conversion system that directly converts DC power into DC power having different voltages, and is widely used. FIG. 3 shows an example of the configuration of a polarity reversal chopper circuit, which is one of the buck-boost chopper circuits.
76.

In FIG. 3, 1 is a DC power source, 2 and 3 are capacitors, 4 is a reactor, 5 is a load, 10 is a DC switch, and 20 is a diode. FIG. 2 shows the operation of the circuit. FIG. 2 (a) shows that the DC switch 10 is turned on.
The off state, (b) is the current waveform of the reactor 4. When the gate of the DC switch 10 is turned on, a current i1 flows,
Energy is stored in the reactor 4. Next, when the DC switch 10 is turned off, a current i2 flows and the energy stored in the reactor 4 is released to the load 5. T is a switching cycle, in which the voltage applied to the load can be made larger or smaller than the power supply voltage by changing the pulse width of the gate signal 1 of the DC switch. In FIG. 3, the polarity of the output voltage is positive on the lower side,
The upper side is negative.

[0004]

When the load current is large, the control can be performed quickly even if the output voltage is increased or decreased by controlling the DC switch, and good characteristics can be obtained. However, when the load current hardly flows If is increased, it takes time for the output side capacitor to discharge when it is decreased, and it is not possible to decrease it to the target value within the desired time. Further, when the load has a bidirectional power flow such as a DC machine, power regeneration cannot be performed. The present invention has been made in view of the above points, and an object of the present invention is to provide a chopper circuit capable of bidirectional power conversion regardless of the state of a load. [Constitution of Invention]

[0005]

To achieve the above object, the present invention provides a DC power supply, a series circuit including a first DC switch and a reactor connected in parallel with the DC power supply,
A load and a first diode connected in parallel to the reactor.
A polarity reversal chopper circuit comprising a series circuit composed of a diode and capacitors connected in parallel to the DC power source and the load, respectively, and a second diode connected in parallel to the first DC switch, and The first dio
The second direct current switch is connected in parallel to the switch.

[0006]

With the above configuration, another polarity reversing chopper in the reverse direction is connected to the polarity reversing chopper circuit to control two DC switches, the first DC switch and the second DC switch. This enables bidirectional power conversion.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the present invention, in which 1 is a DC power source, 2 and 3 are capacitors, 4 is a reactor, 5 is a load,
10 and 11 are semiconductor switching elements (IGBT) 2
0 and 21 are diodes. The operation of the circuit shown in FIG. 1 is divided into the following two. One is when the load current is large. In this case, the circuit including the IGBT 10 and the diode 20 controls the IGBT 10. IGBT10
When is turned on, a current i1 flows and energy is stored in the reactor 4. Next, when the IGBT 10 is turned off, the current i2
The energy stored in the reactor 4 is released to the load 5.

When it is desired to decrease the output voltage in the state where the load current hardly flows, or when the load is in the power regeneration state by the DC machine, the IGBT 11 is controlled by the circuit including the IGBT 11 and the diode 21. When the IGBT 11 turns on, a current i4 flows and energy is stored in the reactor 4. Next, when the IGBT 11 is turned off, a current i3 flows and the energy accumulated in the reactor 4 is released to the DC power source for regeneration.

[0009]

As described above, according to the present invention, the polarity reversal chopper is connected to the polarity reversal chopper in the opposite direction, and by controlling the two DC switches according to the flow of electric power, the load can be controlled in any state. Even if there is, bidirectional power conversion is possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a chopper circuit of the present invention.

2 is a diagram for explaining the operation of the chopper circuit of FIG. 1, (a) is an ON / OFF waveform diagram of a DC switch 10, FIG.
(B) is a current waveform diagram of the reactor 4.

FIG. 3 is a configuration diagram of a conventional polarity reversal chopper circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2, 3 ... Capacitor, 4 ... Reactor, 5 ... Load, 10 ... 1st DC switch, 11 ... 2nd DC switch, 20 ... 1st diode, 21 ... 2nd diode -Do.

Claims (1)

[Claims] 1. A series circuit comprising a direct current power supply and a first direct current switch and a reactor connected in parallel to the direct current power supply,
A load and a first diode connected in parallel to the reactor.
A polarity reversal chopper circuit comprising a series circuit composed of a diode and capacitors connected in parallel to the DC power source and the load, respectively, and a second diode connected in parallel to the first DC switch, and The first dio
A chopper circuit characterized in that a second DC switch is connected in parallel to the switch.