JPH0522929A - Snubber circuit - Google Patents

Abstract

PURPOSE:To regenerate energy, which is stored in a snubber circuit connected with serially connected self-arc-extinguishing semiconductor devices, in a DC power supply, etc., without consuming the energy by a resistance. CONSTITUTION:Self-arc-extinguoishing semiconductor devices 1a, 1b are connected in series via reactor 3; diodes 2a, 2b are connected in reverse-parallel with respective semiconductor devices and a first serial assembly composed of capacitors 6a, 6b and diodes 7a, 7b for determining the charging polyarity of the capacitors is connected in parallel therewith, and a second serial assembly composed of diode 12 and capacitor 11 is connected between the series connections of the capacitors 6a, 6b and diodes 7a, 7b. Then, energy stored in the reactor 3 and capacitors 6a, 6b is recovered into the capacitor 11 and regenerated in a DC power supply, etc., by a power regenerator 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snubber circuit which is a protection circuit connected to self-extinguishing type semiconductor elements connected in series.

[0002]

2. Description of the Related Art When a self-arc-extinguishing semiconductor device, for example, a GTO thyristor is on / off controlled, a snubber circuit must be used in order to prevent device breakdown due to a sharp rise of voltage and current applied to the self-arc-extinguishing semiconductor device. A so-called protection circuit is provided. Hereinafter, the self-extinguishing type semiconductor device is referred to as GTO
It will be described only when it is a thyristor (hereinafter abbreviated as GTO).

FIG. 6 and FIG. 7 are configuration diagrams when a conventional snubber circuit and the snubber circuit are applied to a half bridge of a series-connected GTO inverter. In FIG. 7, the positive arm is composed of GTOs 1a and 1b and the free wheel diodes 2a and 2b connected in antiparallel to the GTO 1a and 1b.
TO1c, 1d and freewheel diode 2c, 2d
It is composed by. Positive arm GTO 1a, 1b
In order to suppress the current increase rate of the above, a snubber circuit composed of the anode reactor 3a, the snubber diode 4a and the snubber resistor 5a is connected. This is especially called a series snubber circuit. In addition, the positive arm GTO1a,
In order to suppress the voltage increase rate applied to each of the 1b, the snubber capacitors 6a, 6b and the snubber diodes 7a, 7b.
b and a snubber circuit composed of snubber resistors 8a and 8b are connected. This is especially called a parallel snubber circuit. The same applies to the negative arm GTOs 1c and 1d. Further, 9 is a DC power source of the inverter, and point A is an output terminal. However, the balance resistance for voltage sharing in the steady state is omitted.

Next, the operation will be described with reference to FIG.
It is assumed that an inductive load (not shown) is connected to the output terminal A of FIG. 7, and the load current I ₀ thereof flows in the direction of the arrow in the figure. The voltage of the DC power supply 9 is E. Now, the positive arms GTO1a, 1b are turned on, and the DC power supply 9-anode reactor 3a-GTO1a-GTO1.
b-The load current I ₀ is flowing through the path of the output terminal A, the voltages of the snubber capacitors 6a and 6b are 0, and the voltages of the snubber capacitors 6c and 6d are respectively charged to E / 2. Consider a case in which the load current I ₀ is cut off by turning off at the same time. When the GTOs 1a and 1b are turned off at the same time, the interrupted load current I ₀ is bypassed to the snubber diode 7a-snubber capacitor 6a-snubber diode 7b-snubber capacitor 6b-output terminal A path to charge the snubber capacitors 6a, 6b. When the charging voltage becomes equal to or higher than E / 2, the freewheel diodes 2c and 2d become conductive, and the load current I ₀ flows through the path of the anode reactor 3b-freewheel diode 2d-freewheel diode 2c-output terminal A.

In this process, the snubber diode 4a becomes conductive, and the current of the anode reactor 3a is changed from the anode reactor 3a-the snubber diode 4a-the snubber resistor 5a-.
Energy stored in the anode reactor 3a that flows back through the path of the anode reactor 3a is consumed by the snubber resistor 5a. Further, the energy stored in the snubber capacitors 6c and 6d is discharged and consumed through the snubber resistors 8c and 8d. GT after turning off GTO1a, 1b
When O1c and 1d are turned on at the same time, the snubber capacitor 6
When energy remains in c and 6d, the snubber capacitor 6c-GTO1c-the snubber resistor 8c-the snubber capacitor 6c path and the snubber capacitor 6d-GTO1d.
-Snubber resistor 8d-Energy is entirely consumed by the snubber resistors 8c and 8d by the path of the snubber capacitor 6d.

Next, consider the case where the GTOs 1c and 1d are simultaneously turned off and then the GTOs 1a and 1b are simultaneously turned on.
At this time, the load current I ₀ is in the direction in the figure, and the GTO1
c and 1d do not interrupt the current. When the GTOs 1a and 1b are turned on at the same time, the energy stored in the snubber capacitors 6a and 6b is stored in the snubber capacitor 6a-the snubber resistor 8a-GTO1a-the snubber capacitor 6a and the snubber capacitor 6b-the snubber resistor 8b-GTO1b-.
Snubber resistors 8a, 8
The snubber capacitors 6c and 6d are consumed by the DC power supply 9b and the DC power source 9-anode reactor 3a-GTO1a-GTO1b.
-Snubber capacitor 6c-Snubber diode 7c-Snubber capacitor 6d-Snubber diode 7d-Anode reactor 3b-DC power source 9 is charged up to E / 2.

Further, the energy stored excessively in the anode reactors 3a and 3b is the anode reactor 3a-
The load current I ₀ is consumed by the snubber resistors 5a and 5b through the snubber resistor 5a, the snubber diode 4a, the anode reactor 3a, and the anode reactor 3b, the snubber resistor 5b, the snubber diode 4b, and the anode reactor 3b. -Anode reactor 3
a-GTO1a-GTO1b-flows through the path of the output terminal A. The above is the load current I ₀ is the description of the operation when flowing in the direction of the arrow in the figure, the load current I ₀
Since the operation when is flowing in the direction opposite to the arrow in the figure is completely symmetrical to the operation described above, the description thereof will be omitted.

[0008]

The conventional snubber circuit is configured as described above, and when applied to a power converter using a self-extinguishing type semiconductor element such as GTO, the snubber circuit is turned on and off. The energy stored in the reactor, which is the energy storage element, will be consumed by the resistor, and if self-extinguishing type semiconductor elements are connected in series, the energy consumed will increase,
There is a problem that the efficiency of the power conversion device is reduced and the cooling component or the device included in the power conversion device becomes large in size, which causes the power conversion device to become large in size. Further, since the energy consumed by the resistor is proportional to the switching frequency of the self-arc-extinguishing type semiconductor element, it is difficult to increase the frequency of the power conversion device.

The present invention has been made to solve the above problems, and consumes energy stored in a snubber circuit connected to a directly connected self-arc-extinguishing type semiconductor element by a resistor. The purpose is to obtain a snubber circuit which has a function of being able to be regenerated to a DC power supply or the like.

[0010]

In the snubber circuit according to the present invention, two self-arc-extinguishing semiconductor elements, which are simultaneously controlled to be turned on and off, are connected in series via an anode reactor, and each of the self-arc-extinguishing semiconductor elements is connected. A series body of a snubber diode and a snubber capacitor is connected to, and a series body of a capacitor and a diode for recovering the energy stored in the anode reactor and the two snubber capacitors is connected, and the energy is extracted from the capacitor and regenerated to a power source or the like. It is equipped with a power regeneration device that can.

[0011]

The snubber circuit according to the present invention suppresses the sharp rise of voltage and current applied to two self-arc-extinguishing type semiconductor elements that are turned on and off at the same time, and the energy stored in the anode reactor and the snubber capacitor that form the snubber circuit. Is recovered by a capacitor for regenerating one energy without being consumed by a resistor, the energy is taken out from the capacitor and regenerated by a power source or the like.

[0012]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of a snubber circuit according to a first embodiment. In the figure, 1a and 1b are GTOs as an example of a self-arc-extinguishing type semiconductor device that is simultaneously on / off controlled.
Reference numerals 2a and 2b are freewheel diodes antiparallelly connected to the GTOs 1a and 1b. Reference numeral 3 is an anode reactor for suppressing a current increase rate applied to the GTOs 1a and 1b. 6a and 6b.
Is a snubber capacitor that suppresses the rate of voltage increase applied to each of the GTOs 1a and 1b, and 7a and 7b are snubber capacitors 6.
a snubber diode that determines the charging polarity of a and 6b, 11 a recovery capacitor for recovering the energy stored in the anode reactor 3 and the snubber capacitors 6a and 6b,
Reference numeral 12 is a recovery diode that determines the charging polarity of the recovery capacitor 11, and reference numeral 13 is an electric power regeneration device that has a function of extracting energy from the recovery capacitor 11 and regenerating it to a power source or the like, and controlling the recovery capacitor 11 to a constant voltage.

FIG. 2 is a block diagram when the snubber circuit of FIG. 1 is applied to a half bridge of a series-connected GTO inverter, and the upper arm and the lower arm are symmetrical circuits. In addition, about the code | symbol attached to the component, what has the same number shall have the same function.
Further, the same reference numerals are attached to the parts having the same configurations as the conventional ones.

The operation of the snubber circuit of the present invention will be described below with reference to FIG. Here, only an operation when an inductive load (not shown) is connected to the output terminal A and the load current I ₀ is flowing in the direction of the arrow in the figure will be described. The load current I ₀ is the reverse of the arrow in the figure. Since the operation when flowing in the direction is completely symmetrical to the operation in the case described above,
Omit it. The voltage of the DC power supply 9 is E, and the recovery capacitors 11a and 11b are the power regeneration device 13a and the power regeneration device 13a, respectively.
It is assumed that the constant voltage e is controlled by 13b.
However, the voltage e is a value that is a fraction of the voltage E.

Now, the GTOs 1a and 1b are turned on, and the DC power supply 9-GTO1a-anode reactor 3a-GT.
The load current I ₀ is flowing through the path of O1b-output terminal A, the voltages of the snubber capacitors 6a and 6b are 0, and the voltages of the snubber capacitors 6c and 6d are E / 2 and the GTO 1a and 1b are simultaneously charged. Consider a case in which the load current I ₀ is cut off by turning it off. When the GTOs 1a and 1b are turned off at the same time, the interrupted load current I ₀ is the snubber capacitor 6a-snubber diode 7a-anode reactor 3a-snubber diode 7b-snubber capacitor 6
The snubber capacitors 6a and 6b are charged by bypassing the path of the b-output terminal A. Their charging voltage is voltage e
In the above case, the recovery diode 12b becomes conductive, the snubber capacitors 6c and 6d start discharging, and the energy stored in them is recovered in the recovery capacitor 11b.

During this period, the initial current of the anode reactor 3a is the anode reactor 3a-snubber diode 7
The energy stored in the anode reactor 3a flows back through the path of b-recovery capacitor 11a-recovery diode 12a-snubber capacitor 7a.
It is collected in a. The snubber capacitors 6a and 6b are charged to E / 2, the snubber capacitors 6c and 6d are discharged to 0, and the load current I ₀ is equal to the free wheel diode 2d-anode reactor 3b-free wheel diode 2c-output terminal A. It will flow according to the route. The snubber capacitors 6a and 6b are charged to a voltage value higher than E / 2, but after the current of the anode reactor 3a becomes 0, the freewheel diode 2d
-Anode reactor 3b-Freewheel diode 2c-Snubber capacitor 6b-Recovery capacitor 11a-
Through the path of the recovery diode 12a, the snubber capacitor 6a, the DC power supply 9 and the freewheel diode 2d, the energy for the overcharge is discharged and settled in E / 2. In that state, turning on the GTOs 1c and 1d does not change the circuit state.

Next, consider a case where the GTOs 1c and 1d are simultaneously turned off and then the GTOs 1a and 1b are simultaneously turned on.
At this time, the load current I ₀ is in the direction in the figure, and the GTO1
c and 1d do not interrupt the current when turned off. GTO
When 1a and 1b are turned on at the same time, the snubber capacitor 6
The energy stored in a and 6b is the snubber capacitor 6a-GTO1a-anode reactor 3a-GTO.
1b-snubber capacitor 6b-recovery capacitor 11a-
The recovery diode 12a and the snubber capacitor 6a are used to recover the recovery capacitor 11a. Load current I ₀
Is a DC power supply 9-GTO 1a-anode reactor 3a
-GTO1b-supplied by the path of the output terminal A,
The current in the path of GTO1a-anode reactor 3a-GTO1b becomes larger than the load current I ₀ , and the current is shunted to the path of snubber capacitor 6c-snubber diode 7c-anode reactor 3b-snubber capacitor 6d, and snubber capacitors 6c, 6d. Will be charged.

The snubber capacitors 6c and 6d are each E / 2.
Once charged, the current equal to or larger than the load current I ₀ of the current of the anode reactor 3a begins to be shunted to the path of the anode reactor 3a-snubber diode 7b-recovery capacitor 11a-recovery diode 12a-snubber diode 7a-anode reactor 3a. The current of the anode reactor 3b is as follows: anode reactor 3b-snubber diode 7d-recovery capacitor 11b-recovery diode 12b-snubber diode 7c-anode reactor 3.
It begins to be diverted to the path of b, and each anode reactor 3
The energy stored in a and 3b is the recovery condenser 11
Collected in a and 11b. In this period, the snubber capacitors 6c and 6d are charged to a voltage value higher than E / 2, but after the current of the anode reactor 3b becomes 0,
The energy of the overcharge is discharged by the path of the snubber capacitor 6d-recovery capacitor 11b-recovery diode 12b-snubber capacitor 6c and settles in E / 2. The discharge current is DC power supply 9-GTO1a-anode reactor 3a-GTO1b. It is superimposed on the load current I ₀ supplied from the path of the output terminal A.

With the above operation, the GTOs connected in series are connected.
To recover all the energy stored in the snubber capacitors 6a, 6b, 6c, 6d that suppress the voltage increase rate of 1a, 1b or 1c, 1d and the anode reactors 3a, 3b that suppress the current increase rate to recovery capacitors 11a, 11b. It was shown that the recovery capacitor 11a
Alternatively, the snubber circuit shows an example of a concrete circuit of the power regeneration devices 13a and 13b having a function of extracting energy from 11b, regenerating it to the power source 9 and the like, and further controlling the recovery capacitor 11 to a constant voltage. Show that it is feasible.

A specific example of the power regeneration circuit 13 is shown in FIG. In FIG. 3, 9a is a direct current power source for regenerating energy, 14a and 14b are self-extinguishing type semiconductor elements, 15a,
15b is a diode and 16 is a reactor. In addition,
As an example, the self-arc-extinguishing type semiconductor elements 14a and 14b may include G
Applying TO.

Now, the GTO 14a, 1 of the power regeneration circuit 13
When 4b are turned on at the same time, the recovery capacitor 11-GTO
The energy stored in the recovery capacitor 11 is transferred to the reactor 16 through the path of 14b-reactor 16-GTO 14a-recovery capacitor 11. Then GTO
When 14a and 14b are turned off, the current flowing in the reactor 16 flows back through the route of the reactor 16-diode 15a-DC power supply 9a-diode 15b-reactor 16, and the energy transferred to the reactor 16 is DC power supply 9a.
Regenerated to. By this series of circuit operations, energy can be extracted from the recovery capacitor 11 and regenerated to the DC power supply 9a. Furthermore, the voltage control of the recovery capacitor 11 is GT
It is easily conceivable that this is possible by controlling the on-time of O14a and 14b.

As described above, the power regeneration circuit 13 provided in the snubber circuit of this embodiment can be realized by a simple circuit, but in addition, it can be realized by applying a known DC-DC converter circuit configuration. Is possible. The DC voltage 9a in FIG. 3 and the DC power supply 9 in FIG. 2 do not necessarily have to be the same. When a multi-phase inverter is configured, the recovery capacitors 11a and 11b of each half bridge are also included.
A configuration in which the upper arm and the lower arm are connected in common and two power regeneration devices 13a and 13b are provided can be easily considered.

Example 2. In the first embodiment of the present invention, the case where it is applied to the inverter has been described, but it is also possible to apply it to the chopper. An example thereof is shown in FIG. In FIG. 4, 17 is a load circuit. The operation of the illustrated circuit is similar to that of the inverter shown in FIG.

Example 3. In FIG. 1 of the first embodiment of the present invention, the recovery capacitor 11 is subjected to constant voltage control by the power regenerator 13, but a transformer can be used as another means for obtaining the same effect. An example of this is shown in FIG. The same circuit operation is performed by setting the turn ratio with the primary winding of the transformer 18. However, considering the reset of the transformer 18, the recovery diode 1 of FIG.
1 is replaced with a self-arc-extinguishing type semiconductor element 19, and it is necessary to turn off when energy regeneration is completed. Also,
As shown in FIG. 5, the diode bridge 1 is provided on the secondary side of the transformer 18.
When 0 is connected to the DC power source 9b that regenerates energy, the same effect as in FIG. 3 is obtained.

[0025]

As described above, according to the present invention, the energy stored in the anode reactor and the snubber capacitor, which are the energy storage elements in the snubber circuit connected to the self-extinguishing semiconductor element, is regenerated to the DC power source or the like. Since it is configured so that a highly efficient power conversion device can be obtained, the cooling device provided in the device can be downsized, the entire device can be downsized, and high-frequency switching of the self-arc-extinguishing type semiconductor element is possible. Can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a snubber circuit of the present invention.

FIG. 2 is a circuit diagram showing an embodiment in which the snubber circuit of the present invention is applied to an inverter half bridge.

FIG. 3 is a circuit diagram showing a specific example of a power regeneration device connected to the snubber circuit of the present invention.

FIG. 4 is a circuit diagram showing an embodiment in which the snubber circuit of the present invention is applied to a chopper.

FIG. 5 is a circuit diagram showing a snubber circuit that achieves the same effects as the snubber circuit of the present invention.

FIG. 6 is a circuit diagram showing a conventional snubber circuit.

FIG. 7 is a circuit diagram showing a case where the conventional snubber circuit is applied to an inverter half bridge in which self-extinguishing semiconductor elements are connected in series.

[Explanation of symbols]

 1a, 1b Self-extinguishing type semiconductor device (GTO) 2a, 2b Freewheel thyroid 3 Anode reactor 6a, 6b Snubber capacitor 7a, 7b Snubber diode 9 DC power supply 11 Recovery capacitor 12 Recovery diode 13, 13a, 13b Power regeneration device

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 7, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

FIG. 6 and FIG. 7 are configuration diagrams when a conventional snubber circuit and the snubber circuit are applied to a half bridge of a series-connected GTO inverter. In FIG. 7, the positive arm is composed of GTOs 1a and 1b and the free wheel diodes 2a and 2b connected in antiparallel to the GTO 1a and 1b.
TO1c, 1d and freewheel diode 2c, 2d
It is composed by. Positive arm GTO 1a, 1b
In order to suppress the current increase rate of the above, a snubber circuit composed of the anode reactor 3a, the snubber diode 4a and the snubber resistor 5a is connected. This is especially called a series snubber circuit. In addition, the positive arm GTO1a,
In order to suppress the voltage increase rate applied to each of the 1b, the snubber capacitors 6a, 6b and the snubber diodes 7a, 7b.
b and a snubber circuit composed of snubber resistors 8a and 8b are connected. This is especially called a parallel snubber circuit. The same applies to the negative arm GTOs 1c and 1d. Further, 9 is a DC power source of the inverter, and point A is an output terminal. However, the balance resistance for voltage sharing in the steady state is omitted .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

[0005] The snubber capacitor 6a in this process,
If 6b is charged to a predetermined voltage, Sunabada diode 4
a conducts, and the current of the anode reactor 3a is the anode reactor 3a-snubber diode 4a-snubber resistor 5
The energy stored in the a-anode reactor 3a is returned to the snubber resistor 5a.
Consumed in. Further, the energy stored in the snubber capacitors 6c and 6d is discharged and consumed through the snubber resistors 8c and 8d. After turning off GTO1a and 1b, G
When energy remains in the snubber capacitors 6c and 6d when the TO1c and 1d are simultaneously turned on, the snubber capacitor 6c-GTO1c-the snubber resistor 8c-the snubber capacitor 6c path and the snubber capacitor 6d-GTO1.
All the energy is consumed by the snubber resistors 8c and 8d through the path of the d-snubber resistor 8d-the snubber capacitor 6d.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

Example 3. In FIG. 1 of the first embodiment of the present invention, the recovery capacitor 11 is subjected to constant voltage control by the power regenerator 13, but a transformer can be used as another means for obtaining the same effect. An example of this is shown in FIG. The same circuit operation is performed by setting the turn ratio with the primary winding of the transformer 18. However considering the resetting of the transformer 18, the recovery of Figure 1 diode 1
2 is replaced with the self-arc-extinguishing type semiconductor element 19, and when the energy regeneration is completed, it is necessary to turn it off. Also,
As shown in FIG. 5, the diode bridge 1 is provided on the secondary side of the transformer 18.
When 0 is connected to the DC power source 9b that regenerates energy, the same effect as in FIG. 3 is obtained.

Claims (1)

Claim: What is claimed is: 1. Two self-arc-extinguishing semiconductor elements that are simultaneously controlled to be turned on and off are connected in series via a reactor, and a diode is connected to each of the self-arc-extinguishing elements in antiparallel. Then, a first series body composed of a capacitor and a diode that determines the charging polarity of the capacitor is connected in parallel to each of the self-extinguishing semiconductor elements, and between the series connection points of the capacitor and the diode of the first series body. Is connected to a second series body composed of a diode and a capacitor, and energy stored in the reactor and the capacitors in the first series bodies is recovered in the capacitors in the second series body, and at the same time, in the second series. A snubber circuit equipped with a power regeneration device that extracts energy from a capacitor in the body and regenerates it into a DC power source.