JPH1155954A - Current source power conversion circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a voltage stress or switching loss during turn-on or turn-off of a semiconductor element constituting a main circuit switch by providing a resonance circuit by a commutation capacitor constituting an auxiliary switch circuit with a commutation reactor. SOLUTION: A current type power converter is constituted of a DC power supply 1, a DC reactor 2, a two-phase main circuit bridge comprising 4 sets of main circuit switches 11 to 14, and a two-phase auxiliary circuit bridge 30 comprising 4 sets of auxiliary switch circuits 31 to 34 and two sets of commutation reactors 21a, 21b. By these, a voltage stress of switching loss during turn-on or turn-off of a semiconductor element constituting the main circuit switches 11 to 14 can be reduced and, as a result, a current type power conversion circuit can be made compact and its conversion efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current-type power conversion circuit for converting DC to AC or for converting AC to DC.

[0002]

2. Description of the Related Art FIG. 6 is a circuit diagram showing a conventional example of a current source inverter as this type of current source power conversion circuit. 6, reference numeral 1 denotes a DC power supply, 2 denotes a DC reactor, 3 denotes a load, 10 denotes a two-phase main circuit bridge, and the two-phase main circuit bridge includes four sets of main circuit switches 11 to 14.
The main circuit switches 11 to 14 are formed by connecting IGBTs 11a to 14a as main self-extinguishing elements and main diodes 11b to 4b, respectively, in series.

In the current source inverter shown in FIG. 6, as is well known, main circuit switches 11 and 14 and main circuit switch 1 are driven by a drive signal from a gate drive circuit (not shown).
By alternately turning on and off 2 and 13, an AC current i _O having an amplitude based on the DC current Id is supplied to the load 3.

[0004]

In the current source inverter shown in FIG. 6, when the main circuit switches 11 to 14 are turned on and off, the parasitic inductance (l) of the wiring connecting the individual components and Due to the switching characteristic (di / dt) of the main circuit switch, v = l · (di / dt) is generated as a jump voltage (v),
This voltage is applied to the main circuit switch, resulting in a voltage stress on the semiconductor elements constituting the main circuit switch,
Further, the switching loss of the element also increases.

Conventionally, in order to cope with the above, the breakdown voltage and capacity of the main circuit switches 11 to 14 are set to be large, and a snubber circuit (not shown) is added. However, in this method, the current type inverter becomes large, There is a disadvantage that conversion efficiency is reduced due to an increase in switching loss.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a current-type power conversion circuit that solves the above-mentioned problems, suppresses the jump voltage, and has a small switching loss.

[0006]

The first aspect of the present invention is a current type power conversion circuit for converting DC to AC or AC to DC, and comprises 2n (n = positive integer) sets of main self-power-supply circuits. A main switch circuit in which an arc-shaped element and a main diode are connected in series; and a second diode and a second diode connected to both ends of a circuit in which the 2n sets of the first self-extinguishing elements and the first diode are connected in series. Both ends of a circuit in which a self-extinguishing element is connected in series are connected in parallel, and a connection point between a first self-extinguishing element and a first diode, and a connection point between a second diode and a second self-extinguishing element And an auxiliary switch circuit having a configuration in which a commutation capacitor is connected between the auxiliary switch circuit and the two auxiliary commutation reactors. Bridge connection of each of the above A phase auxiliary circuit bridge, wherein one commutation reactor is connected between one DC side terminal of the n-phase main circuit bridge and one DC side terminal of the n-phase main circuit bridge; The other commutation reactor is connected between the other DC side terminal of the n-phase auxiliary circuit bridge and the other DC side terminal of the n-phase auxiliary circuit bridge. The circuit bridge is configured such that each AC side terminal is individually connected.

According to a second aspect of the present invention, in the first aspect, each DC side terminal of the n-phase auxiliary circuit bridge is replaced with each DC side terminal of the n-phase main circuit bridge. DC terminal. This third invention is a current-source power conversion circuit for converting DC to AC or AC to DC, wherein 2n (n = positive integer) sets of main self-extinguishing elements and main diodes are connected in series. A main switch circuit connected thereto, and a second diode and a second self-extinguishing element connected in series to both ends of a circuit in which the 2n sets of the first self-extinguishing element and the first diode are connected in series. The two ends of the circuit are connected in parallel, and a commutation capacitor is connected between the connection point of the first self-arc-extinguishing element and the first diode and the connection point of the second diode and the second self-extinguishing element. The auxiliary switch circuit having the above configuration and the 2n commutation reactors are connected, the respective main switch circuits and the respective commutation reactors are individually connected in series, and the main switch circuit and the commutation reactor are connected in series. Bridge connection of each circuit The n-phase main circuit bridge, and each of the auxiliary switch circuits is bridge-connected to form the n-phase auxiliary circuit bridge. Both ends of the DC side terminal of the n-phase main circuit bridge and the DC side of the n-phase auxiliary circuit bridge Both ends of the terminal are connected in parallel, and each AC-side terminal of the n-phase main circuit bridge and each AC-side terminal of the n-phase auxiliary circuit bridge are individually connected.

According to a fourth aspect of the present invention, there is provided a current type power conversion circuit for converting DC to AC or for converting AC to DC,
A main switch circuit formed by connecting 2n (n = positive integer) sets of main self-extinguishing elements and a main diode in series;
A circuit in which a second diode and a second self-extinguishing element are connected in series is connected in parallel to both ends of a circuit in which a set of the first self-extinguishing element and the first diode are connected in series; An auxiliary switch circuit having a configuration in which a commutation capacitor is connected between a connection point between the first self-extinguishing element and the first diode, and a connection point between the second diode and the second self-extinguishing element;
comprising n commutation reactors, bridging each of the main switch circuits to form the n-phase main circuit bridge, individually connecting each of the auxiliary switch circuits and each of the commutation reactors in series, The auxiliary switch circuit and the series circuit of the commutation reactor are each connected in a bridge to form the n-phase auxiliary circuit bridge, and both ends of a DC side terminal of the n-phase main circuit bridge and both ends of a DC side terminal of the n-phase auxiliary circuit bridge. And the AC terminals of the n-phase main circuit bridge and the AC terminals of the n-phase auxiliary circuit bridge are individually connected.

According to a fifth aspect of the present invention, there is provided a current type power conversion circuit for converting DC to AC or for converting AC to DC, wherein 2n (n = positive integer) sets of a main self-extinguishing element and a main diode are provided. And a second switch and a second self-extinguishing element at both ends of a circuit in which the 2n sets of the first self-extinguishing element and the first diode are connected in series. Are connected in parallel at both ends of a circuit formed by connecting the first self-extinguishing element and the first diode,
An auxiliary switch circuit having a configuration in which a commutation capacitor is connected between the second diode and a connection point of the second self-arc-extinguishing element;
Comprising the n commutation reactors, each of the main switch circuits being bridge-connected to form the n-phase main circuit bridge, and each of the auxiliary switch circuits being bridge-connected to form the n-phase auxiliary circuit bridge, Both ends of the DC side terminal of the n-phase main circuit bridge and both ends of the DC side terminal of the n-phase auxiliary circuit bridge are connected in parallel, and the respective AC side terminals of the n-phase main circuit bridge and the n-phase auxiliary circuit bridge The commutation reactors are connected to the respective AC terminals.

According to the present invention, the resonance circuit formed by the commutation reactor and the commutation capacitor constituting the auxiliary switch circuit can reduce the voltage stress at the time of turning on or off the semiconductor element constituting the main circuit switch as described later. Switching loss can be reduced.

[0011]

FIG. 1 is a circuit diagram of a current source inverter as a current source power converter according to a first embodiment of the present invention, and has the same functions as those of the conventional circuit shown in FIG. Those having the same reference numerals. That is, in FIG. 1, a two-phase main circuit bridge 1 including a DC power supply 1, a DC reactor 2, and four sets of main circuit switches 11 to 14 is provided.
0, a two-phase auxiliary circuit bridge 30 including four sets of auxiliary switch circuits 31 to 34, and two sets of commutation reactors 2
1a and 21b. Each of the auxiliary switch circuits 31 to 34 includes an IGBT 31a, 32a, 33a, 34a as a first self-extinguishing element, a first diode 31b, 32b, 33b, 34b, and a second
Diodes 31c, 32c, 33c, 34c and IGBTs 31d, 32d, 33 as second self-extinguishing elements
d, 34d and commutation capacitors 31e, 32e, 33
e and 34e are formed as shown in the figure.

In the current source inverter shown in FIG.
The main circuit switch 11 is turned off (mode 2) from the on state of the main circuit switches 11 and 14 (mode 1), then the main circuit switch 12 is turned on (mode 7), and the main circuit switch 14 is turned off (mode 9). ),
Further, the operation until the main circuit switch 13 is turned on (mode 14) and the main circuit switches 12 and 13 are turned on (mode 15), that is, until the current of the load 3 is reversed will be described below.

First, when the main circuit switches 11 and 14 are turned on (mode 1), a current flows through a path of DC power supply 1 → DC reactor 2 → main circuit switch 11 → load 3 → main circuit switch 14 → DC power supply 1. I have. Next, a drive signal is given to the IGBTs 31a and 31d of the auxiliary switch circuit 31,
When the GBTs 31a and 31d are turned on (mode 2), the current of the main circuit switch 11 through the path of the DC power supply 1 → DC reactor 2 → main circuit switch 11 → load 3 → main circuit switch 14 → DC power supply 1 is commutated. Reactor 2
1a → IGBT 31a → commutation capacitor 31e → IGB
It is reduced by the current in the path of T31d. At this time, the rate of change (di / dt) of the current of the main circuit switch 11 is a value based on the resonance frequency of the commutation reactor 21a and the commutation capacitor 31e. When the current becomes zero, the main circuit switch 11
Is completed.

That is, when the main circuit switch 11 is turned off, the DC power supply 1 → DC reactor 2 → commutation reactor 21a → IGBT 31a → commutation capacitor 31e →
A current flows through the path of the IGBT 31d → the load 3 → the main circuit switch 14 → the DC power supply 1 (mode 3). During the mode 3, the drive signal of the main circuit switch 11 is turned off, but the current of the path continues. (Mode 4).

When the voltage across the commutation capacitor 31e becomes zero due to the current in the mode 4 path (mode 5), the DC power supply 1 → DC reactor 2 → commutation reactor 21a → I
A current flows through the path of the GBT 31a, the first diode 31b and the second diode 31c, the IGBT 31d, the load 3, and the DC power supply 1. When the IGBTs 31a and 31d are turned off by the drive signal during the mode 5 (mode 6), the DC power supply 1 → DC reactor 2 → commutation reactor 21a → second diode 31c → commutation capacitor 31e.
→ first diode 31b → load 3 → main circuit switch 14
→ Current flows in the path of DC power supply 1.

Next, when a drive signal is applied to the main circuit switch 12 to turn on the main circuit switch 12 (mode 7), the current in the path of mode 6 is changed from the DC power supply 1 → DC reactor 2 → main circuit switch 12 → Main circuit switch 14 →
It is reduced by the current in the path of the DC power supply 1. At this time, the rate of change (di / dt) of the current of the auxiliary circuit switch 31 is a value based on the resonance frequency of the commutation reactor 21a and the commutation capacitor 31e. When the current becomes zero, the turn-off operation of the auxiliary switch circuit 31 and the turn-on operation of the main circuit switch 12 are completed, and the mode shifts to mode 8.

In mode 8, current continues to flow through the path of DC power supply 1 → DC reactor 2 → main circuit switch 12 → main circuit switch 14 → DC power supply 1, and thereafter, a drive signal is applied to IGBTs 34a and 34d of auxiliary switch circuit 34. , I
When the GBTs 34a and 34d are turned on (mode 9), the current in the path of DC power supply 1 → DC reactor 2 → Main circuit switch 12 → Main circuit switch 14 → DC power supply 1 is IGBT 34a → Commutation capacitor 34e → IGBT
34d → decreased by the current in the path of the commutation reactor 21b. At this time, the rate of change of the current of the main circuit switch 14 (d
i / dt) is the commutation reactor 21b and the commutation capacitor 3
The value is based on the resonance frequency of 4e. At the end of the period of the mode 9, the current of the main circuit switch 14 becomes zero, and the turn-off operation of the main circuit switch 14 is completed.

That is, when the main circuit switch 14 is turned off, the DC power supply 1 → DC reactor 2 → main circuit switch 12 → IGBT 34a → commutation capacitor 34e → I
A current flows through the path of the GBT 34d → the commutation reactor 21b → the DC power supply 1 (mode 10). During this mode 10, the drive signal of the main circuit switch 14 is turned off, but the current of the path continues (mode 11). ).

When the voltage across the commutation capacitor 34e becomes zero due to the current in the mode 11 path (mode 12),
DC power supply 1 → DC reactor 2 → Main circuit switch 12 →
IGBT 34a, first diode 34b and second diode 34c, IGBT 34d → commutation reactor 21b →
A current flows through the path of the DC power supply 1. When the IGBTs 34a and 34d are turned off by the drive signal during the mode 12 (mode 13), the DC power supply 1 → DC reactor 2
A current flows through the path of the main circuit switch 12, the second diode 34c, the commutation capacitor 34e, the first diode 34b, the commutation reactor 21b, and the DC power supply 1.

Next, a drive signal is supplied to the main circuit switch 13 to turn on the main circuit switch 13 (mode 1).
4) The current in the path of mode 13 is reduced by the current in the path of DC power supply 1 → DC reactor 2 → main circuit switch 12 → load 3 → main circuit switch 13 → DC power supply 1. At this time, the rate of change of the current of the auxiliary circuit switch 34 (di / d
t) is a value based on the resonance frequency of the commutation reactor 21b and the commutation capacitor 34e. At the end of the period of the mode 14, the current of the auxiliary circuit switch 34 becomes zero,
The turn-off operation of the auxiliary switch circuit 34 and the turn-on operation of the main circuit switch 13 are completed, and the mode shifts to mode 15.

In mode 15, DC power supply 1 → DC reactor 2 → Main circuit switch 12 → Load 3 → Main circuit switch 1
3 → By continuing the current in the path of DC power supply 1,
The reversal operation of the current of the load 3 is completed. Note that the period from mode 2 to mode 14 described above is slightly shorter than the period from mode 1 or mode 15.

FIG. 2 is a circuit diagram of a current-source inverter as a current-source power converter according to a second embodiment of the present invention. Those having the same functions as those of the embodiment shown in FIG. The same reference numerals are given. That is, in FIG. 2, a DC power supply 1, a DC reactor 2, and a two-phase main circuit bridge 10 including four sets of main circuit switches 11 to 14,
A two-phase auxiliary circuit bridge 30 including four sets of auxiliary switch circuits 31 to 34, and two sets of commutation reactors 22a,
22b.

The difference between the current source inverter shown in FIG. 2 and the embodiment of FIG. 1 is that the DC reactor 2 is connected to the DC terminal of the two-phase auxiliary circuit bridge 30. The operation of the current-source inverter is almost the same as the operation of the embodiment circuit shown in FIG. FIG. 3 is a circuit diagram of a current-source inverter as a current-source power converter according to a third embodiment of the present invention. Components having the same functions as those of the embodiment shown in FIG. It is attached.

That is, in FIG. 3, a DC power supply 1, a DC reactor 2, four sets of main circuit switches 11 to 14 and four commutation reactors 23a to 23d are individually connected in series. The circuit comprises a two-phase main circuit bridge 10a formed by bridge-connecting circuits, and a two-phase auxiliary circuit bridge 30 comprising four sets of auxiliary switch circuits 31 to 34.

The difference between the current source inverter shown in FIG. 3 and the embodiment shown in FIG. 1 is that the above-described two-phase main circuit bridge 10a is provided. Since the operation of the circuit of the embodiment of FIG. 1 is substantially the same as that of the embodiment shown in FIG. FIG. 4 is a circuit diagram of a current-source inverter as a current-source power converter according to a fourth embodiment of the present invention. Components having the same functions as those of the embodiment shown in FIG. It is attached.

That is, in FIG. 4, a DC power supply 1, a DC reactor 2, a two-phase main circuit bridge 10 composed of four sets of main circuit switches 11 to 14, four sets of auxiliary switch circuits 31 to 34, and four Commutation reactor 24a
To 24d are individually connected in series, and a two-phase auxiliary circuit bridge 30a is formed by bridging these series circuits.

The difference between the current source inverter shown in FIG. 4 and the embodiment of FIG. 1 is that the above-described two-phase auxiliary circuit bridge 30a is provided. Since the operation of the circuit of the embodiment of FIG. 1 is substantially the same as that of the embodiment shown in FIG. FIG. 5 is a circuit diagram of a current-source inverter as a current-source power converter according to a fifth embodiment of the present invention. Components having the same functions as those of the embodiment shown in FIG. It is attached.

That is, in FIG. 5, a two-phase main circuit bridge 10 comprising a DC power supply 1, a DC reactor 2, four sets of main circuit switches 11 to 14, and a two-phase main circuit bridge consisting of four sets of auxiliary switch circuits 31 to 34. Auxiliary circuit bridge 30
And two sets of commutation reactors 25a and 25b. The point that the current source inverter shown in FIG. 5 is different from the circuit of the embodiment of FIG. 1 is that the commutation reactors 25a and 25
5b are connected between the respective AC terminals of the two-phase main circuit bridge 10 and the respective AC terminals of the two-phase auxiliary circuit bridge 30. Is almost the same as the operation of the circuit of the embodiment of FIG. 1 described above, and the description thereof will be omitted.

In the first to fifth embodiments, the circuit applied to the two-phase current source inverter has been described. However, the circuit of the present invention can be applied to a three-phase or more voltage source inverter and current source converter. Can be applied.

[0030]

According to the present invention, as described above, the voltage at the time of turning on or off the semiconductor element constituting the main circuit switch is achieved by the resonance circuit including the commutation reactor and the commutation capacitor constituting the auxiliary switch circuit. Since the stress and the switching loss can be reduced, the current-type power conversion circuit is reduced in size and the conversion efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a current-source power conversion circuit showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a current-source power conversion circuit according to a second embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a current source power conversion circuit showing a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a current-source power conversion circuit showing a fourth embodiment of the present invention.

FIG. 5 is a circuit diagram of a current source power conversion circuit according to a fifth embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of a current source power conversion circuit showing a conventional example.

[Explanation of symbols]

1 DC power supply 2 DC reactor 3 Load 10
10a: Main circuit bridge, 11 to 14: Main circuit switch, 21a, 21b, 22a, 22b, 23a to 23
d, 24a to 24d, 25a, 25b ... commutation reactor, 30, 30a ... auxiliary circuit bridge, 31 to 34 ... auxiliary switch circuit, 31e to 34e ... commutation capacitor.

Claims (5)

[Claims] 1. A current type power conversion circuit for converting DC to AC or AC to DC, wherein 2n (n = positive integer) sets of main self-extinguishing elements and a main diode are connected in series. A second switch and a second self-extinguishing element are connected in series at both ends of a circuit in which the 2n sets of the first self-extinguishing element and the first diode are connected in series. Both ends of the circuit are connected in parallel, and a commutation capacitor is connected between a connection point between the first self-arc-extinguishing element and the first diode and a connection point between the second diode and the second self-extinguishing element. An auxiliary switch circuit having a configuration, and two commutation reactors, wherein each of the main switch circuits is bridge-connected to form the n-phase main circuit bridge, and each of the auxiliary switch circuits is bridge-connected to the n-phase main circuit. Auxiliary circuit bridge One commutation reactor is connected between one DC side terminal of the n-phase main circuit bridge and one DC side terminal of the n-phase auxiliary circuit bridge, and the other DC side terminal of the n-phase main circuit bridge The other commutation reactor is connected between the other DC side terminal of the n-phase auxiliary circuit bridge, and each AC side terminal of the n-phase main circuit bridge and each AC side of the n-phase auxiliary circuit bridge A current source power conversion circuit, wherein terminals are individually connected. 2. The current-source power conversion circuit according to claim 1, wherein each of the DC-side terminals of said n-phase auxiliary circuit bridge is replaced with each of said DC-side terminals of said n-phase main circuit bridge. A current-source power conversion circuit, characterized in that it is a DC terminal of the circuit. 3. A current-source power conversion circuit for converting direct current to alternating current or alternating current to direct current, wherein 2n (n = positive integer) sets of main self-extinguishing elements and main diodes are connected in series. A second switch and a second self-extinguishing element are connected in series at both ends of a circuit in which the 2n sets of the first self-extinguishing element and the first diode are connected in series. Both ends of the circuit are connected in parallel, and a commutation capacitor is connected between a connection point between the first self-arc-extinguishing element and the first diode and a connection point between the second diode and the second self-extinguishing element. An auxiliary switch circuit having the above configuration, and the 2n commutation reactors, wherein the main switch circuits and the commutation reactors are individually connected in series, respectively, and a series circuit of the main switch circuit and the commutation reactors is provided. Bridge each one The n-phase main circuit bridge is connected to each of the auxiliary switch circuits to form the n-phase auxiliary circuit bridge. Both ends of the DC side terminal of the n-phase main circuit bridge and the DC side of the n-phase auxiliary circuit bridge Current source power, characterized in that both ends of the terminal are connected in parallel, and each AC side terminal of the n-phase main circuit bridge and each AC side terminal of the n-phase auxiliary circuit bridge are individually connected. Conversion circuit. 4. A current-source power conversion circuit for converting DC to AC or AC to DC, wherein 2n (n = positive integer) sets of main self-extinguishing elements and a main diode are connected in series. A second switch and a second self-extinguishing element are connected in series at both ends of a circuit in which the 2n sets of the first self-extinguishing element and the first diode are connected in series. Both ends of the circuit are connected in parallel, and a commutation capacitor is connected between a connection point between the first self-arc-extinguishing element and the first diode and a connection point between the second diode and the second self-extinguishing element. An auxiliary switch circuit having a configuration, and the 2n commutation reactors, wherein each of the main switch circuits is bridge-connected to form the n-phase main circuit bridge, and each of the auxiliary switch circuits and the respective commutation reactors Each individually The n-phase auxiliary circuit bridge is formed by connecting the auxiliary switch circuit and the commutation reactor in series with each other in the form of a bridge, and both ends of the DC side terminal of the n-phase main circuit bridge and the DC of the n-phase auxiliary circuit bridge Both ends of the side terminal are connected in parallel, and each AC side terminal of the n-phase main circuit bridge and each AC side terminal of the n-phase auxiliary circuit bridge are individually connected. Current source power conversion circuit. 5. A current type power conversion circuit for converting DC to AC or AC to DC, wherein 2n (n = positive integer) sets of main self-extinguishing elements and a main diode are connected in series. A second switch and a second self-extinguishing element are connected in series at both ends of a circuit in which the 2n sets of the first self-extinguishing element and the first diode are connected in series. Both ends of the circuit are connected in parallel, and a commutation capacitor is connected between a connection point between the first self-arc-extinguishing element and the first diode and a connection point between the second diode and the second self-extinguishing element. An auxiliary switch circuit having the above configuration, and the n commutation reactors, wherein each of the main switch circuits is bridge-connected to form the n-phase main circuit bridge, and each of the auxiliary switch circuits is bridge-connected to the n-phase main circuit. Phase auxiliary circuit bridge Both ends of the DC side terminal of the n-phase main circuit bridge and both ends of the DC side terminal of the n-phase auxiliary circuit bridge are connected in parallel, and each AC side terminal of the n-phase main circuit bridge and the n-phase auxiliary circuit A current-source power conversion circuit, wherein the commutation reactor is connected between each of the AC terminals of the bridge.