JPH0522953A - Power conversion device - Google Patents

Abstract

PURPOSE:To provide a power conversion device having excellent efficiency by regenerating energy stored in an anode reactor to an AC power when a self-arc-extinguishing type semiconductor element is turned OFF in the power converter constituted by connecting the anode reactor in series with the self-arc- extinguishing type semiconductor element connected on the positive electrode side of at least a DC power. CONSTITUTION:In a power conversion device organized by connecting an anode reactor 1 in series with a self-arc-extinguishing type semiconductor element bonded with the positive electrode side of at least a DC power 2, an inverter 4 for regeneration, in which DC input terminals are connected at both ends of the anode reactor 1, and an AC power 6, in which AC power output from the inverter 4 for regeneration is regenerated through an isolating transformer 5, are provided, and the inverter 4 for regeneration has a function keeping the DC circuit voltage within a fixed range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention keeps the voltage of the anode reactor within a certain range when the self-extinguishing type semiconductor device is turned off, regenerates a part of its energy to an AC power supply, and suppresses snubber circuit overvoltage. The present invention relates to a power converter that reduces the loss.

[0002]

2. Description of the Related Art As a conventional technique related to the technique of the present invention, FIG. 5 shows an example of the configuration of a power converter which consumes energy of an anode reactor by a resistor. FIG. 5 is an example in which a half-bridge inverter is configured using a self-arc-extinguishing type semiconductor device (hereinafter, simply referred to as GTO).

A series circuit of a resistor 35 and a diode 2 is connected in parallel to an anode reactor (hereinafter simply referred to as AL) 1. One end of AL1 to which the resistor 35 is connected is connected to the positive side of the DC power supply 21. The other end of AL1 is connected to the anode of GTO 11a. GT
A diode 12a is connected in antiparallel to O11a. A snubber circuit 13a is further connected in parallel to the GTO 11a. The cathode of GTO11a is the output terminal 2
2 and the anode of GTO 11b. G
Similarly to 11a, the diode 12b is connected to the TO 11b in anti-parallel, and the snubber circuit 13b is connected in parallel. The cathode of the GTO 11b is connected to the negative side of the DC power supply 21.

When the GTO 11a is turned off, the current flowing through the AL1 until then begins to decrease, and a voltage proportional to the current change rate is generated across the AL1. This voltage turns on the diode 2, and a circulating current flows through the path of the diode 2, the resistor 35, and AL1. Due to this circulating current, the energy accumulated in AL1 is transferred to the resistor 35.
Consumed in. The resistor 35 suppresses the increase in the voltage across AL1 and prevents the overvoltage from being applied to the GTOs 11a and 11b and other main circuits. Figure 6
Is a configuration example of the snubber circuit 13. A snubber capacitor 51 and a snubber resistor 52 are connected in series, and a snubber diode 53 having the illustrated polarity is connected in parallel to the snubber resistor 52. The terminal A of the snubber circuit 13 is the GTO 11
And the terminal B is connected to the cathode of the GTO 11.

[0005]

The conventional power conversion device as described above has the following drawbacks.

FIG. 5 shows a circuit in which the energy of AL1 is consumed by the resistor 35. When the current interrupted by the GTO 11 increases and the number of interruptions (switching frequency) increases, the energy consumed by the resistor 35 increases,
This reduces the efficiency of the entire device. Moreover, since the current of AL1 decreases exponentially, if the breaking current is large,
The current may not reach 0 within the off time of the GTOs 11a and 11b. In addition, the voltage of the snubber circuit rises and the GTO
Since an overvoltage is transiently applied to 11a and the snubber circuit 13 loss increases, it is necessary to make the apparatus such as cooling equipment larger than necessary.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and the AL energy is not consumed by the resistance, and the snubber circuit loss is reduced. An object is to provide a conversion device.

[0008]

In order to achieve the above object, the present invention comprises an anodic reactor connected in series to a self-arc-extinguishing type semiconductor device connected to at least the positive electrode side of a DC power supply. In the power conversion device, a regenerative inverter having DC input terminals connected to both ends of the anodic reactor, and an AC power source for regenerating AC power output from the regenerative inverter via an insulating transformer, In addition, the regeneration inverter is characterized by having a function of keeping the DC circuit voltage within a certain range.

[0009]

As described above, with the configuration, the electromagnetic energy stored in the AL is regenerated to the AC power source, for example, via the regeneration inverter and the insulation transformer, so that the loss can be reduced and the snubber circuit overvoltage can be suppressed. be able to.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the block diagram of FIG.

One end of AL1 is connected to the positive side of the DC power supply 21. Also, this terminal is the N of the regeneration inverter 4.
It is connected to the side terminal. The other end of AL1 is connected to the anode of the self-arc-extinguishing semiconductor element 11a and the anode of the diode 2. The cathode of the diode 2 is connected to the P-side terminal of the regenerative inverter 4. The AC output of the regenerative inverter 4 is supplied to the AC power supply 6 via the insulation transformer 5.
It is connected to the. Since the configuration other than the above is the same as that of FIG. 5, the description thereof will be omitted.

FIG. 2 shows an example of the configuration of the regenerative inverter 4 used in this embodiment. The input terminal P is a voltage divider 41b
, Filter capacitor 42, self-extinguishing semiconductor element 4
It is connected to the collectors of 3b and 43d. Voltage divider 41
The other end of b is connected to the control circuit 46 and the voltage divider 41a. A synchronous power supply 45 and a current detector 44 are further connected to the control circuit 46. The output of the control circuit 46 is connected to the gates of the self-extinguishing semiconductor devices 43a to 43d. The emitter of the self-extinguishing semiconductor element 43b is the collector of the self-extinguishing semiconductor element 43a and the current detector 4
4 is connected. The other end of the current detector 44 is connected to the insulating transformer 5. The input terminal N is connected to the other end of the voltage divider 41a, the other end of the filter capacitor, and the emitters of the self-turn-off semiconductor devices 43a and 43c.

Next, the operation of the present invention will be described with reference to FIG. When the self-extinguishing semiconductor element 11a turns off,
Similar to FIG. 5, the current flowing through AL1 starts to decrease, and a voltage is generated across AL1. When this voltage exceeds the voltage ER kept within a certain range by the regenerative inverter 4, the diode 2 turns on and a current flows through the regenerative inverter 4. Since the voltage across AL1 is kept within a certain range by the regenerative inverter 4, the current flowing through AL1 decreases at a constant rate of change. At this time, the energy stored in AL1 is regenerated by the regenerative inverter 4 through the insulating transformer 5 to the AC power supply 6.

Next, the operation of the regenerative inverter 4 will be described with reference to FIG. In FIG. 2, the voltage ER between the input terminals P and N is divided by the voltage dividers 41a and 41b and input to the control circuit 46. In the control circuit 46, electric power is calculated from the voltage ER between the P and N terminals and the synchronous power supply 45 so that the voltage ER between the P and N terminals becomes a constant value, the output current command is calculated, and the current detector 44 is operated. The gates of the self-extinguishing semiconductor elements 43a to 43d are controlled so that the output current detected by the output current command coincides with the output current command.

In this way, the voltage ER is kept within a fixed range by the regenerative inverter 4, so that the voltage across AL1 becomes constant regardless of the magnitude of the breaking current.
Therefore, the current of AL1 decreases at a constant rate of change. As a result, the energy of AL1 is quickly regenerated. Loss is reduced because the electromagnetic energy stored in AL1 is regenerated. Further, the overvoltage of the snubber circuit 13a can be suppressed, and the loss of the snubber circuit can be reduced. Further, transient overvoltage applied to the self-extinguishing semiconductor element 11a can be suppressed. FIG. 3 is a block diagram showing another embodiment of the present invention in which ALs are distributed and arranged.

The ALs 1a and 1b are connected to the positive side and the negative side of the DC power source 21, respectively. At the same time, the output of the regenerative inverters 4a, 4b on the AC side is isolated by the insulating transformers 5a, 5b.
It is connected to the AC power supply 6 via b. AL1a, 1
The other end of b is the anode of the self-extinguishing semiconductor element 11a,
It is connected to the cathode of 11b, the anode of diode 2a, and the cathode of 2b, respectively. Diodes 12a and 12b are connected in anti-parallel, and snubber circuits 13a and 13b are connected in parallel to the self-extinguishing semiconductor elements 11a and 11b. The cathode of the self-extinguishing type semiconductor element 11a is
It is connected to the anode of the self-extinguishing semiconductor element 11b and to the output 22b. The present invention can be applied regardless of how AL is distributed (arrangement, number of dispersions, etc.).

FIG. 4 is a block diagram showing still another embodiment of the present invention in which a plurality of 2-arm type inverters are connected in parallel and the regeneration inverter is common. AL1a, self-arc-extinguishing type semiconductor elements 11a, 11b, diode 12a,
12b, the snubber circuit 13a. The structure of the 2-arm bridge circuit composed of 13b is the same as that shown in FIG. AL1b, self-extinguishing semiconductor element 11c,
11d, diodes 12c and 12d, a snubber circuit 13
c. The structure of another 2-arm bridge circuit composed of 13d is also the same as that of FIG. AL
1a and 1b are connected in parallel to the same regenerative inverter 4 via diodes 2a and 2b. As in the present embodiment, for the AL whose one end is connected to the same potential, the regeneration inverter is commonly used, and the device can be downsized. In the present embodiment, a configuration example for two pairs of single-phase bridge circuits having a two-arm configuration has been described, but the same configuration can be applied to three or more pairs of bridge circuits or multiple bridge circuits. Further, as shown in FIG. 3, even when the ALs are distributed and arranged, the same configuration is possible for the ALs connected to the same potential.

[0018]

As described above, since the electromagnetic energy stored in the AL is regenerated to the AC power source via the regeneration inverter and the insulation transformer, the loss can be reduced and the snubber circuit overvoltage can be suppressed. ..

[Brief description of drawings]

FIG. 1 is a configuration diagram of a power conversion device showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a specific example of the regeneration inverter of FIG.

FIG. 3 is a configuration diagram of a power conversion device showing another embodiment of the present invention.

FIG. 4 is a configuration diagram of a power conversion device showing still another embodiment of the present invention.

FIG. 5 is a configuration diagram of a conventional power conversion device.

FIG. 6 is a configuration diagram of a snubber circuit.

[Explanation of symbols]

 1, 1a to 1d ... Anode reactor 2, 2a to 2d ... Diodes 4, 4a to 4d ... Regenerative inverter 5, 5a to 5d ... Insulation transformer 6 ... AC power supply 11, 11a to 11b ... Self-extinguishing type semiconductor elements 12, 12a to 12b ... Diodes 13, 13a to 13b ... Snubber circuit 21 ... DC power sources 22, 22a-22b ... Output terminals 41a, 41b ... Voltage divider 42 ... Filter capacitors 43a-43d ... Self-extinguishing type semiconductor device 44 ... Current detector 45 ... Synchronous power supply 46 ... Control circuit 51 ... Snubber capacitor 52 ... Snubber resistance 53 ... Snubber diode

Claims (1)

Claim: What is claimed is: 1. A power converter comprising a anodic reactor connected in series with a self-arc-extinguishing semiconductor element which is connected to at least the positive electrode side of a DC power source. A regenerative inverter having DC input terminals connected to both ends thereof and an AC power source for regenerating AC power output from the regenerative inverter via an insulating transformer, and the regenerative inverter has a DC circuit. An electric power converter having a function of keeping a voltage within a certain range.