JPH0866011A - Gate driver for semiconductor switching element - Google Patents

Abstract

PURPOSE: To enhance the uniformity of gate trigger for a switching element and the environmental resistance of an apparatus by connecting a control signal supply circuit and a bias voltage supply circuit, on the output side thereof, in series between the gate-cathode of the semiconductor switching element. CONSTITUTION: The gate driver for semiconductor switching element comprises a control signal supply circuit including a trigger pulse generating circuit and a gate drive transformer 10, and a bias voltage supply circuit including a bias power supply 13, a bias transformer 11, a rectification diode 6, a smoothing capacitor 7, a filter inductor 8 and a bypass capacitor 9. The control signal supply circuit and the bias voltage supply circuit are connected in series, on the output side thereof, between the gate-cathode of a semiconductor switching element 1a. Consequently, a uniform control signal can be fed to each semiconductor switching element 1a and the environmental resistance can be enhanced since no optical fiber is employed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate drive device for a semiconductor switching element applied to a power conversion device such as a high voltage pulse power supply or an inverter.

[0002]

2. Description of the Related Art Semiconductor switching elements such as thyristors and gate turn-off silicon controlled rectifiers (hereinafter referred to as GTOs) have a limited withstand voltage, and a high withstand voltage switch is formed by connecting a plurality of elements in series and driving them simultaneously. Make up.

GTO with conventional gate drive
FIG. 2 shows a high voltage pulse generation circuit using a switch.
When the high breakdown voltage GTO switch 1 configured by connecting the GTOs 1a in series as shown in FIG. 2 is used, the GTOs 1a are at different potentials.

Conventionally, when driving a plurality of switching elements having different potentials as described above, turn-on and turn-off trigger generating circuits 16a to 16d are provided for each element, and in order to drive these elements simultaneously, turn-on is performed. , Turn-off signal generation circuit 17 to optical fiber 1
At 8, a signal is sent to the trigger generation circuits 16a to 16d to generate turn-on and turn-off triggers.

[0005]

In the conventional GTO gate drive device, as described above, each of a plurality of elements is provided with a turn-on and turn-off trigger generation circuit, and this trigger generation circuit is necessary for the number of elements. I was trying.

Further, since the triggers generated by the non-uniformity of the characteristics of the elements in each trigger generation circuit are also non-uniform, the turn-on and turn-off timings of each switching element are varied.

Further, the commercially available optical fiber connector used as a signal transmission means cannot be used in insulating oil, so that it is difficult to use the switching element in oil.

The present invention has been made to solve the above problems, and has as its object the improvement of the uniformity of the gate trigger for a plurality of switching elements, the simplification of the gate drive circuit, and the improvement of the environment resistance. Is.

[0009]

[Means for Solving the Problems]

(1) A gate drive device for semiconductor switching elements according to the present invention is a gate drive device for semiconductor switching elements that are connected in series to form a high breakdown voltage switch, and a bias is applied between the gate and cathode of each semiconductor switching element. A bias voltage supply circuit for supplying a voltage and a control signal supply circuit for supplying a control signal for turning on / off the semiconductor switching element between the gate / cathode of each semiconductor switching element are provided, and the control signal supply circuit includes For a trigger pulse generating circuit that generates a trigger pulse, and a gate drive that connects the generating circuit to the primary winding and has a plurality of secondary windings with the same number of turns to output a control signal to each semiconductor switching element. And a gate of the control signal supply circuit. Each of the drive for the transformer of 2
The secondary winding and the output side of the bias voltage supply circuit are connected in series between the gates / cathodes of the respective semiconductor switching elements.

(2) The present invention is the gate drive device for a semiconductor switching element according to the invention (1), wherein the bias voltage supply circuit is a bias power supply for generating a bias voltage, and the power supply is the primary side. Bias transformer connected to the windings and having the same number of secondary windings as the number of semiconductor switching elements and the same number of secondary windings, a rectifying diode connected to each secondary winding of the same transformer, and the same rectifier A smoothing capacitor connected in parallel to each diode, a filter inductor having one end connected to one end of the capacitor, and one end connected to the other end of the inductor and the other end connected to the other end of the smoothing capacitor. It is formed by a bypass capacitor that outputs a bias voltage from both ends of the capacitor. It is.

[0011]

In the invention (1), since the bias voltage is constantly applied from the bias voltage supply circuit between the gate and the cathode of each semiconductor switching element, the voltage varies between the gate and the cathode. Even if there is, it is possible to prevent erroneous firing of the semiconductor switching element, and the high withstand voltage switch can maintain a stable OFF state.

When the semiconductor switching device in which the trigger pulse generating circuit of the control signal supply circuit generates a trigger pulse is driven, this trigger pulse is output as a control signal via the gate drive transformer and is superimposed on the bias voltage. While being applied between the gate / cathode of each of the semiconductor switching elements and the control signal is being applied, each semiconductor switching element is in the ON state and the high breakdown voltage switch is energized.

Since the control signal applied to each of the semiconductor switching elements is output from the secondary winding of the gate drive transformer having the same number of windings, the control signal has more variation than that of the conventional device. A small number of signals can be obtained, and stable firing of the semiconductor switching element is possible.

Further, since the semiconductor switching elements are all turned on and off by electric signals and the optical fiber used in the conventional apparatus is unnecessary, it can be used in insulating oil and the environment resistance is improved. To do.

In the above invention (2), the bias voltage generated by the bias power source is divided into a plurality of bias voltages by the plurality of secondary windings of the bias transformer, and each is rectified by a rectifying diode. , Smoothed by a smoothing capacitor and a filter inductor, and applied between the gate and cathode of each semiconductor switching element.

Since the secondary windings of the bias transformer have the same number of turns, the bias voltages output from them are equal, and the voltages are rectified by the rectifying diode and smoothed by the smoothing capacitor and the filter inductor. Therefore, the high withstand voltage switch can maintain a stable off state.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A GTO gate drive device according to an embodiment of the present invention will be described with reference to FIG. The present embodiment shown in FIG. 1 is a case where the GTO switch 1 is applied to a high-voltage pulse generator, and the GTO switch 1 includes a plurality of GTOs 1a.
Are connected in series to form a switch having a large withstand voltage.

In the above high voltage pulse generator, when charges are first stored in the charging capacitor 4 and the GTOs 1a are turned on all at once, LC resonance occurs after the assist time by the saturable inductor 3 and the load capacitor 5 is pulsed. Is applied.

The GTO gate drive apparatus according to the present embodiment shown in FIG. 1 includes a bias voltage supply circuit for outputting a bias voltage for supplying each of a plurality of GTOs 1a, and a control signal for turning on each GTO 1a. A control signal supply circuit for outputting is provided, and the bias voltage and the control signal are superimposed and applied between the gate and cathode of each GTO 1a.

The bias voltage supply circuit for outputting the above bias voltage includes a bias power supply 13 for generating a bias voltage, and a plurality of GTs in which the power supply 13 is connected to the primary winding.
A biasing transformer 11 having the same number of secondary windings as O1a, rectifying diodes 6 connected to the respective secondary windings of the transformer 11, smoothing capacitors 7 connected in parallel to the rectifying diodes 6, respectively. A filter inductor 8 whose one end is connected to one end of the smoothing capacitor 7, and one end of which is connected to the other end of the inductor 8 and the other end of which is the same as the other end of the smoothing capacitor 7.
Bypass capacitor 9 connected to the cathode of TO1a
It is formed by.

The control signal supply circuit is the GTO1.
A trigger pulse generating circuit 12 for generating a trigger pulse for turning on a, and the trigger pulse generating circuit 12 is connected to the primary winding and has a plurality of GTO1a and the same number of secondary windings as the respective secondary windings. One end of the side winding is each GTO
It is formed by a gate drive transformer 10 connected to the gate of 1a and the other end thereof connected to one end of each bypass capacitor 9 of the bias voltage supply circuit.

In the above description, in the bias voltage supply circuit, the bias voltage generated by the bias power supply 13 is constantly supplied to the rectifier diode 6 via the bias transformer 11, and after being rectified here, the capacitor 7 is rectified. Then, the voltage is supplied to the capacitor 9 through the smoothing circuit including the inductor 8 and the voltage applied across the capacitor 9 is applied between the gate and the cathode of the GTO 1 as a bias voltage.

This bias voltage prevents erroneous firing of the GTO 1a due to a change in the voltage applied between the gate / cathode of the GTO 1a, so that the GTO switch 1 can maintain a stable off state.

The bias voltage differs depending on the element used and needs to be a voltage corresponding to each element, but the potential may be any voltage that can maintain a stable off state. In addition, a plurality of 2 provided on the transformer 11
The number of turns of the secondary winding is the same.

Regarding the control signal supply circuit, the GTO 1a
At the time of driving, the trigger pulse output from the trigger pulse generation circuit 12 is transmitted through the transformer 10 to the capacitor 9
Is supplied to. The supplied trigger pulse is superimposed on the bias voltage as a control signal, and the gate / gate of the GTO 1a is
Applied between the cathodes, while the control signal is applied,
The GTO 1a is turned on.

At this time, since the trigger pulse is blocked by the filter inductor 8, the trigger pulse does not flow into the bias voltage supply circuit side. That is, the inductor 8 simultaneously performs the smoothing operation of the bias voltage and the inflow preventing operation of the trigger pulse to the bias voltage supply circuit. The number of turns of the plurality of secondary windings provided in the transformer 10 is the same.

In the present embodiment, since the trigger pulse generating circuit outputs the control signal from the secondary winding having the same number of turns in each transformer connected to the primary winding, G
The variation of the turn-on of the TO can be suppressed, and the bias voltage supply circuit is provided to allow the GTO to be
Since a bias voltage is applied between the gate and cathode of the GTO switch, a stable OFF state of the GTO switch can be maintained, and since signal transmission by optical fiber is not required unlike the conventional device, it can be used in insulating oil. It is also possible to improve the environment resistance.

In the present embodiment, the GTO, which is an element capable of controlling both on-time and off-time by a gate signal, has been described, but it is also applicable to an element capable of controlling only on-time. is there.

[0029]

The gate drive device for a semiconductor switching element of the present invention is provided with a trigger pulse generating circuit and a gate drive transformer, a control signal supply circuit for outputting control signals from a plurality of output sides, a bias power supply, and a bias. Transformer, a rectifying diode, a smoothing capacitor, a filter inductor, and a bypass capacitor are provided, and a bias voltage supply circuit that outputs a bias voltage from a plurality of output sides is provided, and each output side of the control signal supply circuit and the bias voltage supply circuit is provided. Are connected in series between the gate / cathode of each semiconductor switching element, a control signal with little variation can be given to each semiconductor switching element, and a stable OFF state of the semiconductor switching element can be maintained. Optical fiber It needs no Buru allows the use of an insulating oil, it is possible to improve the environmental resistance.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional device.

[Explanation of symbols]

 1 GTO Switch 1a GTO 2 Feedback Diode 3 Magnetic Assist Inductor 4 Charging Capacitor 5 Load Capacitor 6 Rectifying Diode 7 Smoothing Capacitor 8 Filter Inductor 9 Bypass Capacitor 10 Gate Drive Transformer 11 Bias Transformer 12 Trigger Pulse Generation Circuit 13 Bias Power Supply

Claims (2)

[Claims] 1. A gate drive device for a semiconductor switching element, which is connected in series to form a high breakdown voltage switch, comprising: a bias voltage supply circuit for supplying a bias voltage between the gate / cathode of each semiconductor switching element; A control signal supply circuit for supplying a control signal for turning on / off the semiconductor switching element is provided between the gate / cathode of each semiconductor switching element, and the control signal supply circuit generates a trigger pulse and a trigger pulse generation circuit. The same generation circuit is connected to the primary winding, and a plurality of secondary windings having the same number of turns are formed by a gate drive transformer that outputs a control signal to each semiconductor switching element, and the control signal is supplied. Each secondary winding of the circuit gate drive transformer and above Each output side of the bias voltage supply circuit is connected to the gate / gate of each semiconductor switching element.
A gate drive device for a semiconductor switching element, which is connected in series between cathodes. 2. The gate drive device for a semiconductor switching element according to claim 1, wherein the bias voltage supply circuit is a bias power source that generates a bias voltage, and the power source is connected to the primary winding. Two bias transformers each having the same number of turns as the number of the semiconductor switching elements and two secondary side windings, and
A rectifying diode connected to the secondary winding, a smoothing capacitor connected in parallel to each rectifying diode, a filter inductor having one end connected to one end of the capacitor, and one end connected to the other end of the inductor. A gate drive device for a semiconductor switching element, wherein the other end is formed by a bypass capacitor connected to the other end of the smoothing capacitor and outputting a bias voltage from the both ends.