JP2551089Y2 - Parallel connection circuit of switching elements with improved current balance - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel connection circuit of switching elements having improved current balance, and more particularly, to a circuit for connecting a plurality of transistors or gate turn-off thyristors (hereinafter referred to as GTO) in parallel. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel connection circuit of switching elements with improved current balance at the time of off.

[0002]

2. Description of the Related Art When a plurality of switching elements through which a large current flows are connected in parallel, it is necessary to balance the currents flowing through the plurality of switching elements so that a large current does not flow through a specific switching element. Therefore, conventionally, for example, when a transistor is connected in parallel as a switching element, a wiring configuration as shown in FIG. 3 has been used.

In FIG. 3, transistors 1 and 2 are connected in parallel, 11 and 21 are collector terminals of the transistors, 12 and 22 are base terminals,
13 and 23 are emitter terminals for connection to the base drive circuit, 14 and 24 are emitter terminals for main circuit wiring, 3 is a base drive circuit, and 41 to 46 are current-carrying conductors for main circuit wiring.

Conventionally, in order to balance the main circuit currents of the transistors 1 and 2, as shown in FIG.
6, the same circuit impedance was used for the main circuit of transistors 1 and 2. However, in the wiring configuration as described above, due to the difference in the turn-off characteristics between the transistor 1 and the transistor 2, the current flowing during the turn-off transition may be unbalanced. This is particularly true as the wiring impedance from the transistors 1 and 2 to the base drive circuit 3 increases.
The imbalance was great.

FIG. 4 is an operation waveform diagram in a parallel circuit of transistors having the conventional wiring configuration shown in FIG.
In the figure, (a) is a collector current waveform of the transistor 1, (b) is a collector current waveform of the transistor 2,
(C) is a base current waveform of the transistor 1, and (d) is a base current waveform of the transistor 2. As shown in FIG. 4, if the base-emitter of the transistor 1 reversely recovers first at the point (a) in FIG. 4 due to the difference between the turn-off characteristics of the transistors 1 and 2, the collector current of the transistor 2 becomes As shown in the waveform (b) of FIG. 4, the voltage rapidly increases before the reverse recovery occurs between the base and the emitter of the transistor 2 at the point (a).

The time from the point (A) to the point (A) greatly depends on the wiring impedance from the transistor 2 to the base driving circuit 3, and the longer the wiring impedance, the longer the time. The increase in the collector current of No. 2 increases.

[0007]

As described above, in the conventional parallel connection circuit, the increase in the collector current of the transistor which is turned off later becomes large. Therefore, in order to safely turn off the transistor below the rated breaking current value at turn-off while considering this increased current,
This means that a large amount of collector current cannot flow in a steady state.

That is, although the transistors are connected in parallel to increase the current, the object cannot be sufficiently achieved. The present invention has been made in view of the above-described drawbacks of the related art, and it is possible to minimize the imbalance of current sharing during turn-off transition even if there is a difference in the turn-off characteristics of the switching element. It is an object to provide a parallel connection circuit of elements.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a parallel connection circuit of switching elements in which a plurality of switching transistors or gate turn-off thyristors are connected. Between the emitter terminals connected to the base drive circuit or between the gate terminals of the respective gate turn-off thyristors and between the cathode terminals connected to the gate drive circuit with the shortest distance
While providing a current-carrying conductor, the current-carrying conductor and the base terminal and
And the base drive circuit with each connection point between the
The conductor and the gate terminal and the cathode terminal
Wiring means to connect each connection point of
In addition, the present invention is configured to improve imbalance of current sharing when a plurality of switching elements connected in parallel are turned off.

[0010]

The switching elements connected in parallel are connected between the respective base terminals and between the emitter terminals connected to the base driving circuit, or connected between the gate terminals of the respective gate turn-off thyristors and connected to the gate driving circuit. Current conduction connecting the cathode terminals with the shortest distance
Body, and the current-carrying conductor, the base terminal and the air terminal.
Each connection point with the mitter terminal and the base drive circuit, or
Each connection between the current-carrying conductor and the gate terminal and the cathode terminal
The Rukoto provided an interconnection means for connecting the attachment point and the gate drive circuit, turn the parallel-connected switching elements
When turning off, the reverse bias current previously flowing through the switching element whose base-emitter reversely recovers
The current quickly flows into the switching element that has not been recovered through the current-carrying conductor .

For this reason, the reverse bias current of the switching element that has not been reversely recovered increases, and the turn-off time is shortened. Therefore, an increase in the main circuit current during the turn-off transition can be minimized.

[0012]

FIG. 1 is a view showing one embodiment of the present invention, and FIG. 1 is a view showing an embodiment in which a transistor is used as a switching element. 3, the same components as those of the conventional example of FIG. 3 are denoted by the same reference numerals.
The embodiment of FIG. 1 differs from the conventional example of FIG. 3 in that a current-carrying conductor for connecting the emitter terminals 13 and 23 and the base terminals 12 and 22 of the transistors 1 and 2 with the shortest distance. That is, 51 and 52 are additionally connected.

FIG. 2 is an operation waveform diagram in the transistor parallel circuit of the above embodiment, and FIG.
Is a collector current waveform of the transistor 1, (b) is a collector current waveform of the transistor 2, and (c) is a transistor 1
(D) is a base current waveform of the transistor 2. Next, the operation of the present embodiment shown in FIG. 1 will be described with reference to FIG.

In FIG. 2, when transistors 1 and 2 turn off, transistor 1
When the transistor is turned off earlier, at point (a), after the base-emitter reverse recovery of the transistor 1, the reverse bias current of the transistor 1 is changed to the current-carrying conductors 51 and 5.
2 flows quickly from the emitter of the transistor 2 toward the base.

As a result, as shown in a waveform (d) of FIG. 2, the base reverse bias current of the transistor 2 sharply increases, and the reverse recovery between the base and the emitter of the transistor 2 is quickly performed. Therefore, the increase in the collector current of the transistor 2 can be minimized as shown by the waveform (b) in FIG.

In the above embodiment, an embodiment using a transistor as a switching element has been described.
It is needless to say that the switching element in the present invention is not limited to a transistor, but can be applied to other switching elements such as GTO which are turned off by passing a reverse bias current. Further, in the above embodiment, an example of the parallel connection of two transistors has been described. However, the present invention is not limited to the above embodiment, and is also applicable to the parallel connection of an arbitrary number of two or more switching elements. can do.

[0017]

[Effect of the invention] As is clear from the above explanation,
In the present invention, in the switching elements connected in parallel, by a simple configuration of wiring the shortest distance between the base terminal and the emitter terminal of each switching element, or between the gate terminal and the cathode terminal,
The current balance at the time of turn-off transition can be improved, which is extremely effective for increasing the current by connecting the switching elements in parallel.

[Brief description of the drawings]

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

FIG. 2 is an operation waveform diagram of the embodiment of the present invention.

FIG. 3 is a diagram showing a wiring configuration of a conventional parallel-connected transistor.

FIG. 4 is an operation waveform diagram in a wiring configuration of a conventional parallel-connected transistor.

[Explanation of symbols]

1, 2 Transistor 3 Base drive circuit 11, 21 Collector terminal 12, 22 Base terminal 13, 23 Emitter terminal for connection to base drive circuit 14, 24 Emitter terminal for main circuit wiring 41, 42, 43, 44, 45 , 46 Current-carrying conductors for main circuit wiring 51, 52 Current-carrying conductors

Claims (1)

(57) [Scope of request for utility model registration] In a parallel connection circuit of a plurality of switching elements connected to a plurality of switching transistors or gate turn-off thyristors, between a base terminal of each transistor and an emitter terminal connected to a base drive circuit, or A current-carrying conductor is connected between the gate terminals of each gate turn-off thyristor and the cathode terminal connected to the gate drive circuit with the shortest distance, and
Each connection point and base between the body and the base and emitter terminals
Drive circuit, or the current-carrying conductor and gate terminal and
Connect each point of connection with the cathode and cathode terminals to the gate drive circuit
Wiring means for connecting a plurality of switching elements connected in parallel.
A parallel connection circuit of switching elements with improved current balance, characterized in that the imbalance of current sharing at the time of OFF is improved.