JPH07264875A - Controller for semiconductor power converter - Google Patents

Abstract

PURPOSE:To provide a controller for semiconductor power converter which can break an overcurrent without blowing a fuse by controlling the gate of a GTO. CONSTITUTION:A controller for semiconductor power converter is provided with a gate controlling means 6 which controls the switching of turn-off thyristors 1UP-1WN, overcurrent detecting means 4 which detects the flowing states of overcurrents to the thyristors 1UP-1WN, and control means 8 which fetches the detecting output of the detecting means 4 and controls the controlling operation of the controlling means 6 based on the fetched detecting output. When the detecting means 4 detects the flowing state of an overcurrent to one of the thyristors 1UP-1WN, the control means 8 maintains the switching control operating state of the controlling means 6 at the detecting time and, at the same time, controls the voltage across the gate and cathode of the thyristor so as to set the thyristor to a normal operation mode in which a gate is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a power semiconductor converter using a gate turn-off thyristor (hereinafter referred to as GTO) which is a self-extinguishing element, and more particularly to a GTO.
The present invention relates to a control device for controlling stop of a power semiconductor converter or the like when an abnormality such as an overcurrent state or an abnormality in a gate control circuit occurs.

[0002]

2. Description of the Related Art FIG. 1 shows an example of a main circuit of a three-phase PWM power converter using a GTO. In the figure, 1 is a GTO, 2 is a flywheel diode, 3
Is a smoothing capacitor, 4 is an AC side current detector, 5 is a DC side current detector, 6 is a GTO gate control circuit, and is an individual gate control unit 6 circuit corresponding to each GTO of the main circuit,
Each GTO is composed of individual gate control units 6UP to 6WN.

Reference numeral 7 is a fuse, 8 is a control circuit, and 50 is a power source. A known example of a PWM converter using a GTO (Hitachi Review VOL75, No. 6, 1993-5, PP31
~ 34), the GTO switching frequency 50
AC / DC power conversion is performed by turning on / off according to a PWM signal of 0 Hz. The GTO has a function of turning on by supplying an on-gate current to the gate, and interrupting a current flowing through the GTO by supplying an off-gate current. In order to control the on / off state of the GTO, a gate circuit is important as shown in a publicly known example ("Power Electronics & AC Drive" P17-18 published by Denki Shoin).
Although a circuit such as 13 is used, as shown in FIG. 2 of the present specification, an on-gate circuit (a circuit having a function of flowing an on-gate current when the GTO is on) 10, an off-gate circuit (GTO
In general, a circuit having a function of supplying an off-gate current at the time of turning off and a function of applying a reverse bias at the time of turning off) 11 and power circuits 12 and 13 for turning on and off are generally used.

In the above structure, the GTO has conventionally performed gate control so that the off operation is not performed when the current flowing exceeds the maximum breaking current because the element is damaged when the off operation is performed.

Further, when the ON / OFF control of the GTO is performed under the condition where the on-gate current and the off-gate current are insufficient, the element is damaged. Therefore, when the gate control circuit is abnormal, the ON / OFF control is not newly performed and the current state is maintained. I was doing gate control to leave it.

[0006]

In the prior art described above, for example, as shown in FIG. 4, when the GTO 1UP in the main circuit is in the ON state and the gate control section 6UP becomes abnormal and the ON gate current flows, the gate operation is performed. V phase of power supply 50 → diode 2VP
→ GTO1UP → U phase of power supply 50 and W phase of power supply 50 → Diode 2WP → GTO1UP → U phase of power supply 50 The AC short-circuit mode is set and AC short-circuit current continues to flow until fuse 7UP is cut off. .

Further, as shown in FIG. 5, U in the control circuit 8 is
When the phase PWM signal generation unit 9 becomes abnormal and the ON signal of GTO 1UP is released from the gate pulse control unit 6UP of the gate circuit 6, the V phase of the power supply 50 → the diode 2VP →
GTO1UP → U phase of power supply 50 and W phase of power supply 50 → diode 2WP → GTO1UP → U phase of power supply 50 Overcurrent, and AC short-circuit current continues to flow until fuse 7UP is cut off.

As described above, in the past, the element was prevented from being damaged by cutting off the current by fusing the fuse. However, the disadvantage is that the fuse must be blown and the fuse must be replaced, which is expensive. there were.

Further, there has been a problem that the scope of the accident is expanded and it takes time to recover the accident.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a control device for a power semiconductor converter capable of cutting off a current without melting a fuse by gate control of a GTO. To aim.

[0011]

A control device for a power semiconductor converter according to the present invention is a control device for a power semiconductor converter which performs power conversion from AC to DC or from DC to AC using a gate turn-off thyristor. Gate control means for controlling switching of the turn-off thyristor, overcurrent detection means for detecting a state in which an overcurrent flows in the turn-off thyristor, and detection output of the overcurrent detection means, and the gate control based on the detection output. A control means for controlling the control operation of the means, the control means, when the overcurrent detection means detects an overcurrent flowing in the turn-off thyristor, the gate control means at the time of the detection. While maintaining the switching control operation state of the gate-cathode of the turn-off thyristor And controls the voltage such that the turn-off thyristor is gate suppression under normal thyristor operation mode.

The control device for the power semiconductor converter according to the present invention comprises:
In a control device for a power semiconductor converter that performs power conversion from AC to DC or from DC to AC using a gate turn-off thyristor, an on-gate current required to turn on the gate turn-off thyristor is applied to the gate of the gate turn-off thyristor. An on-gate circuit for supplying, an off-gate circuit for supplying an off-gate current necessary for turning off the gate turn-off thyristor to a gate of the gate turn-off thyristor,
For the on-gate circuit and the off-gate circuit,
A power supply circuit for supplying energy required to supply the on-gate current and the off-gate current to the gate turn-off thyristor; and an overcurrent detection means for detecting a state in which an overcurrent of an allowable breaking current or more flows in the gate turn-off thyristor, And a control means for controlling the control operation of the on-gate circuit and the off-gate circuit based on the detection output of the overcurrent detection means, the control means being configured to control the turn-off thyristor by the overcurrent detection means. When a state in which an overcurrent flows in the turn-off thyristor is detected, the control operation state of the on-gate circuit and the off-gate circuit at the time of the detection is maintained, and the voltage between the gate and cathode of the turn-off thyristor is gate-suppressed by the turn-off thyristor. It goes into the normal thyristor operation mode And controlling the.

The control device for the power semiconductor converter according to the present invention comprises:
In a control device for a power semiconductor converter that performs power conversion from AC to DC or from DC to AC using a gate turn-off thyristor, an on-gate current required to turn on the gate turn-off thyristor is applied to the gate of the gate turn-off thyristor. An on-gate circuit for supplying, an off-gate circuit for supplying an off-gate current necessary for turning off the gate turn-off thyristor to a gate of the gate turn-off thyristor,
For the on-gate circuit and the off-gate circuit,
A power supply circuit that supplies energy required to supply the on-gate current and the off-gate current to the gate turn-off thyristor; and an abnormality detection unit that detects an abnormal state of the on-gate circuit, the off-gate circuit, and the power supply circuit,
And a control unit that controls the control operation of the on-gate circuit and the off-gate circuit based on the detection output of the abnormality detection unit, the control unit including the on-gate circuit and the off-gate by the abnormality detection unit. When it is detected that an abnormality has occurred in any of the circuit and the power supply circuit, while maintaining the control operation state of the on-gate circuit and the off-gate circuit at the time of detection,
The voltage between the gate and the cathode of the turn-off thyristor is controlled so that the turn-off thyristor is in a gate-pressed normal thyristor operation mode.

The control device for the power semiconductor converter according to the present invention comprises:
The control means maintains the control operation state of the on-gate circuit and the off-gate circuit at the time of detection when the state in which the overcurrent flows in the turn-off thyristor is detected by the overcurrent detection means, and It is characterized in that control is performed so as to cut off the supply of energy for generating an on-gate current from the on-gate current energy supply unit, which is the supply source of the on-gate current, to the on-gate circuit.

The control device for the power semiconductor converter according to the present invention comprises:
When the abnormality detecting unit detects that an abnormality has occurred in any of the on-gate circuit, the off-gate circuit, and the power supply circuit, the control unit determines the control operation state of the on-gate circuit and the off-gate circuit at the time of the detection. The power supply circuit is controlled so as to cut off the supply of energy for generating an on-gate current from the on-gate current energy supply unit, which is the supply source of the on-gate current, to the on-gate circuit.

According to the present invention, a gate suppress signal having a gate-cathode voltage of, for example, 0 volt, which is neither an on-gate current nor an off-gate current (including reverse bias) as a gate signal of the GTO, is applied to turn off the GTO. It is operated as a normal thyristor mode with no function, and interrupts the current after waiting for a change in the direction of the AC short-circuit current.

[0017]

In the controller of the power semiconductor converter having the above structure,
Since the GTO has the same operation function as a normal thyristor that does not have a gate turn-off function, the polarity of the power supply in the AC short-circuited state changes and the current is limited by the power supply.
When the current is cut off by the GTO and the polarity of the power supply voltage changes again, there is no on-gate signal, so the GT is restarted.
O never turns on. Therefore, it becomes possible to cut off the overcurrent without blowing the fuse.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a three-phase PWM power converter to which the present invention is applied. Since the power converter shown in FIG. 1 has already been described, duplicate description will be omitted. FIG. 3 shows the configuration of an embodiment of the gate control circuit which is a feature of the present invention. In the figure, the gate control circuit includes an on-gate circuit 10, an off-gate circuit 11, an on-gate supply power supply circuit 12, an off-gate supply power supply circuit 13, an on-gate switch 14, an off-gate switch 15, and a limiting resistor for controlling an on-gate current. 16 and smoothing capacitor 1
7, 18, rectifying circuits 19, 20, insulating pulse transformers 21, 22, and on-gate switching power supply circuit 2
3 and an off-gate switching power supply circuit 24.

The on-gate switch 14 and the off-gate switch 15 are switching-controlled by an on-gate signal and an off-gate signal output from the control circuit 8, respectively.

On-gate switching power supply circuit 2
Reference numeral 3 has a function of stopping the energy supply to the on-gate circuit 10 via the insulating pulse transformer 21 by the on-gate power supply stop signal output from the control circuit 8.

The off-gate switching power supply circuit 24 has a function of stopping the energy supply to the off-gate circuit 11 by the off-gate power supply stop signal output from the control circuit 8.

In the above structure, when the above-mentioned gate circuit abnormality occurs as shown in FIG. 4, the V phase of the power source 50 →
Diode 2VP → GTO1UP → U phase of power supply 50 and W phase of power supply 50 → Diode 2WP → GTO1UP → U phase of power supply 50 The AC voltage shown in FIG. 6 (b) and FIG. 6 (c) is applied, and GTO1UP is applied. 6d, a short-circuit current as shown in FIG. 6D flows from time t1 when an abnormality occurs, and from time t2, the V phase of the power supply 50 → diode 2VP → GTO1U.
A reverse voltage is applied to the path of P → U phase of the power supply 50, and from t3, the W phase of the power supply 50 → diode 2WP → GTO1UP.
→ A reverse voltage is applied to the U-phase path of the power source 50, and the overcurrent becomes 0 at time t4.

Here, in the present invention, as shown in FIG. 7, the control circuit 8 locks the on / off operation by the on-gate signal and off-gate signal of the GTO 1UP at the time of the abnormality detection (time t2) of the gate controller 6UP, that is, the on-gate. The operation and the off-gate operation are not newly performed and the current state is maintained, and a stop signal is output to the on-gate switching power supply 23 to stop the power supply to the on-gate circuit 10. As a result, the charging of the smoothing capacitor 17 of the on-gate circuit 10 is stopped, the voltage of the smoothing capacitor 17 becomes 0 at time t3 as shown in FIG. 7 (f) due to the discharge by the on-gate current, and the gate-cathode voltage of GTO1UP becomes 0. Becomes That is, GTO1UP is controlled in the gate suppress state. As a result, the GTO1UP operates in the same way as an ordinary gate-suppressed thyristor.
At time t4, the current flowing in the GTO1UP becomes 0, so that it is turned off. At time t5, the on-gate current is not supplied even if the forward voltage is applied again, so that it is not turned on again and the overcurrent can be interrupted.

The rise of the short-circuit current flowing in the GTO 1UP is suppressed by the impedance of the power supply, the peak value is suppressed to a constant value, and the fuse does not melt down by one AC short-circuit current, so that the fuse melts. It is possible to cut off for one cycle.

Further, when the overcurrent is detected, the overcurrent can be interrupted without the fuse being blown by controlling the gate in the same manner.

Next, FIG. 8 shows a specific example of the gate control unit having a function of detecting an abnormality in the gate circuit and the gate power supply circuit. In the figure, the gate control unit includes an on-gate power supply circuit 12B having an abnormality detection function, a switching power supply circuit 23B, a pulse transformer 21B, and a rectifier circuit 1.
9B, diodes 50 to 52, and pulse transformer 21
B input primary winding 53, output secondary winding 54, abnormality detection tertiary winding 55, abnormality detection circuit 56, and rectifier circuit 5
7 and a determination circuit 58.

The determination circuit 58 compares the reference voltage with the rectified voltage of the detection output of the tertiary winding 55 of the pulse transformer 21B, and when it is less than or equal to the reference voltage, determines that there is an abnormality.

In the above structure, for example, when an abnormality occurs in which the capacitor 17 is short-circuited, the output of the secondary winding 54 is short-circuited and the detection voltage of the tertiary winding 55 is lowered. As a result, the rectified voltage, which is the output voltage of the rectifier circuit 57, also decreases, and when the rectified voltage becomes equal to or lower than the reference voltage level, it is determined that the gate circuit is abnormal.

Also, when an abnormal condition such as a diode short circuit or a pulse transformer winding short circuit occurs, the detection output of the tertiary winding 55 of the pulse transformer 21B similarly decreases, so that these abnormal conditions can be detected.

[0030]

According to the present invention, overcurrent can be interrupted by utilizing the function of the GTO element without damaging the GTO element and without melting the fuse.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an example of a three-phase PWM power conversion device to which the present invention is applied.

FIG. 2 is a circuit diagram showing a configuration of a conventional gate control unit.

3 is a circuit diagram showing a configuration of an embodiment of a gate control unit in FIG.

FIG. 4 is an explanatory diagram showing an overcurrent path when the gate control unit is abnormal.

FIG. 5 is an explanatory diagram showing an overcurrent path when the PWM signal generating unit is abnormal.

FIG. 6 is an explanatory diagram showing an overcurrent interruption waveform according to the present invention.

FIG. 7 is a timing chart showing a GTO gate control operation at the time of abnormality detection according to the present invention.

FIG. 8 is a circuit diagram showing a configuration of a main part of a gate control unit having a function of detecting an abnormality in a gate circuit and a gate power supply circuit.

[Explanation of symbols]

 1 GTO 2 Flywheel diode 3 Smoothing capacitor 4 AC side current detector 5 DC side current detector 6 Gate control circuit 7 Fuses 8 Control circuit 10 On-gate circuit 11 Off-gate circuit 12 On-gate power supply circuit 13 Off-gate power supply circuit 14 On Gate switch 15 Off-gate switch 16 Limiting resistor 17 Smoothing capacitor 18 Smoothing capacitor 19 Rectifier circuit 20 Rectifier circuit 21 Insulation pulse transformer 22 Insulation pulse transformer 23 On-gate switching power supply circuit 24 Off-gate switching power supply circuit 56 Abnormality detection circuit 57 Rectification circuit 58 Judgment circuit

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H02M 7/155 G 9180-5H

Claims (5)

[Claims] 1. A control device for a power semiconductor converter for converting power from AC to DC or DC to AC using a gate turn-off thyristor, comprising: gate control means for controlling switching of the turn-off thyristor; and the turn-off thyristor. An overcurrent detection means for detecting a state in which an overcurrent flows through the control circuit, and a control means for fetching the detection output of the overcurrent detection means and controlling the control operation of the gate control means based on the detection output. The means maintains the switching control operation state of the gate control means at the time of detection when a state in which an overcurrent is flowing in the turn-off thyristor is detected by the overcurrent detection means, and the gate of the turn-off thyristor. The turn-off thyristor gate suppresses the voltage across the cathode Device for controlling a power semiconductor converter, characterized in that controlled to be a normal thyristor operation mode. 2. A control device for a power semiconductor converter for converting power from alternating current to direct current or direct current to alternating current using a gate turn-off thyristor, wherein an on-gate current required to turn on the gate turn-off thyristor is applied to the gate. An on-gate circuit that supplies the gate of a turn-off thyristor, an off-gate circuit that supplies an off-gate current necessary to turn off the gate turn-off thyristor to the gate of the gate turn-off thyristor, and the on-gate circuit and the off-gate circuit, respectively,
A power supply circuit for supplying energy required to supply the on-gate current and the off-gate current to the gate turn-off thyristor; and an overcurrent detection means for detecting a state in which an overcurrent of an allowable breaking current or more flows in the gate turn-off thyristor, A turn-off thyristor by the overcurrent detection means, the control means controlling the control operation of the on-gate circuit and the off-gate circuit based on the detection output of the overcurrent detection means. When a state in which an overcurrent flows through the turn-off thyristor is detected, the control operation state of the on-gate circuit and the off-gate circuit at the time of the detection is maintained and the voltage between the gate and cathode of the turn-off thyristor is gate-suppressed by the turn-off thyristor. Normal thyristor operation mode Device for controlling a power semiconductor converter, characterized by controlled so. 3. A control device for a power semiconductor converter for converting power from alternating current to direct current or direct current to alternating current using a gate turn-off thyristor, wherein an on-gate current required to turn on the gate turn-off thyristor is applied to the gate. An on-gate circuit that supplies the gate of a turn-off thyristor, an off-gate circuit that supplies an off-gate current necessary to turn off the gate turn-off thyristor to the gate of the gate turn-off thyristor, and the on-gate circuit and the off-gate circuit, respectively,
A power supply circuit that supplies energy required to supply the on-gate current and the off-gate current to the gate turn-off thyristor, an abnormality detection unit that detects an abnormal state of the on-gate circuit, the off-gate circuit, and the power supply circuit, and the abnormality detection unit And a control means for controlling the control operation of the on-gate circuit and the off-gate circuit on the basis of the detection output, wherein the control means includes the on-gate circuit, the off-gate circuit and the power supply circuit by the abnormality detection means. When it is detected that an abnormality has occurred in any of the above, while maintaining the control operation state of the on-gate circuit and the off-gate circuit at the time of the detection, the turn-off thyristor controls the voltage between the gate and cathode of the turn-off thyristor. Gate suppressed normal thyristor motion Device for controlling a power semiconductor converter and controls so that the mode. 4. The control means maintains the control operation state of the on-gate circuit and the off-gate circuit at the time of detection when a state in which an overcurrent flows through the turn-off thyristor is detected by the overcurrent detection means. The power supply circuit is controlled to cut off the supply of energy for generating an on-gate current from the on-gate current energy supply unit, which is the supply source of the on-gate current, to the on-gate current. A control device for the power semiconductor converter according to claim 1. 5. The control means, when the abnormality detecting means detects that an abnormality has occurred in any of the on-gate circuit, the off-gate circuit and the power supply circuit, the on-gate circuit and the off-gate circuit at the time of the detection. Control operation state is maintained, and control is performed so as to cut off the supply of energy for generating an on-gate current from the on-gate current energy supply unit, which is a supply source of the on-gate current, of the power supply circuit. The control device for a power semiconductor converter according to claim 3, wherein