JPH063872B2 - Semiconductor - Google Patents

Description

The present invention relates to a bidirectional energization type semiconductor breaker.

[Conventional technology]

A bidirectional energizing type semiconductor breaker is shown in FIG.

In the figure, 11 is a DC power supply, 13 is a load, and a forward conduction gate turn-off thyristor (hereinafter referred to as GTO thyristor) 2 and a reverse conduction GTO thyristor 3 are connected in parallel between them, and a diode is connected to these GTO thyristors 2 and 3. 5, 6, 7 and 8 and a bridge rectification type snubber circuit 14 composed of a capacitor 4 are connected in parallel, and a voltage dependent non-linear resistor such as a ZnO arrester 9 is connected in parallel.

In the capacitor 4 of the bridge rectification type snubber circuit 14,
Discharge resistors 10 and 11 and a GTO for discharge inserted between them
A series circuit composed of thyristors 12 is connected.

FIG. 5 is an operation waveform diagram of the bidirectional energization type semiconductor circuit breaker. (A) is an on signal, (b) is an off signal, (c) is a load current, and (d) is a main terminal a ₁ -a _2. Voltage, E is the voltage of the DC power supply 1, and Er is the limiting voltage of the ZnO arrester 9.

As shown in (b), an off signal is applied to the gates of both GTO thyristors 2 and 3 at time t ₀ , and both GTs
The O thyristors 2 and 3 remain off.

At time t ₁ , the off signal is removed and the on signal is transmitted to both GTs.
GTO for discharge given to the gates of O-thyristors 2 and 3
It is also given to the gate of the thyristor 12 at the same time. As a result, the GTO thyristor 2 having the polarity of the voltage between the main terminals a _{1 and} a ₂ is turned on (FIG. 5 (a), (b), (c),
(See (d)), and the load current increases from zero (see FIG. 5 (c)).

At time t ₂ , the ON signal is removed and the OFF signal is output to both GTs.
It is applied to the gates of the O thyristors 2 and 3 (also applied to the gate of the GTO thyristor 12), and the GTO thyristor 2 is turned off. Since the load current flows into the capacitor 4 through the diodes 5 and 6, the voltage between the main terminals rises. Eventually, the voltage between the main terminals becomes the limit voltage Er of the arrester 9.
And the load current commutates to the ZnO arrester 9 (5th
(See Figure (d)).

At time t ₃ , the load energy is consumed by the ZnO arrester 9, and the load current is attenuated to zero. The capacitors 4 are disconnected from the main terminals a ₁ and a ₂ because the diodes 5 and 6 are turned off, and the voltage between the main terminals tends to settle down to the DC power supply voltage. However, the parasitic capacitance of the ZnO arrester 9 is large, and when the load current becomes zero, the inductance 13a of the load 13 and ZnO
Resonant vibration of LC occurs between the parasitic capacitances 15 of the arrester 9. Eventually, at time t ₄ , the DC power supply voltage E is attenuated by the resistance component of the circuit of the voltage between the main terminals. This completes the operation of the bidirectional energizing circuit breaker.

[Problems to be solved by the invention]

As described above, in the conventional circuit shown in FIG. 4, when the load current becomes zero, LC resonance vibration occurs between the load inductance 13 and the ZnO arrester parasitic capacitance 15 and the system becomes unstable. . In general, ZnO arrester 9
The difference between the limiting voltage Er and the DC power supply voltage E is large, and the amplitude of the vibration is large. Furthermore, if the resistance of the circuit is small, the decay time will be very long.

An object of the present invention is to eliminate the disadvantages of the above-mentioned conventional example, to promptly damp parasitic oscillation between the parasitic capacitance of the ZnO arrester and the inductance of the load, which occurs when the load current (fault current) is cut off, and to maintain the stability of the system. It is to provide a semiconductor breaker capable of

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention combines antiparallel 1
A pair of gate turn-off thyristors, a bridge rectification type snubber circuit including a diode and a capacitor, and a Zn
In a bidirectional energization type semiconductor circuit breaker in which voltage-dependent nonlinear resistance elements such as O arresters are connected in parallel, resonance vibration occurs between the parasitic capacitance of the voltage-dependent nonlinear resistance element and the inductance of the load when the semiconductor circuit breaker is cut off. The gist is that a series circuit of a resistor and a capacitor for attenuating is connected in parallel to the voltage-dependent nonlinear resistance element.

[Action]

According to the present invention, the resistor and the capacitor connected in parallel to the ZnO arrester together with the inductance of the load cause the RLC
Vibration damping circuit. This vibration damping circuit prevents parasitic vibration that occurs between the parasitic capacitance of the ZnO arrester and the load inductance when the load current is cut off, and makes it possible to maintain the stability of the system.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the semiconductor breaker of the present invention, and FIG. 2 is an operation waveform diagram of the circuit shown in FIG. 1, which has the same components as those shown in FIGS. Are denoted by the same reference numerals.

That is, for the parallel circuit of the forward direction GTO thyristor 2 and the reverse direction thyristor 3 between the direct current 1 and the load 13, the bridge rectification type snubber circuit 14 and the nonlinear resistor ZnO arrester by the diodes 5, 6, 7, 8 and the capacitor 4 are provided. 9 and 9 are connected in parallel, and the capacitors 4 of the bridge rectification type snubber circuit 14 have discharging resistors 10 and 11 and a discharging thyristor 12 respectively.
Is the same as that of the conventional example.

The present invention further includes a resistor 16 and a capacitor in such a circuit.
Seventeen series connection circuits were connected in parallel to the ZnO arrester 9.

The main operation is omitted the description the same as the prior art shown in the fifth figure, resistor 16, the value R of the capacitor 17, at time t ₃ as shown in FIG. 2 by appropriately selecting the C ( When the load current attenuates to zero) The voltage between the main terminals a _{1 and} a ₂ can be attenuated to the power supply voltage E without vibration.

Incidentally, the selection of R and C is performed as follows.

The circuit of FIG. 1 is basically represented by the equivalent circuit shown in FIG. 3, and the characteristic equation of this circuit is a cubic equation S ³ LCC ₀ R +
S ² L (C + C ₀ ) + SCR + 1 = 0 (1)

Therefore, if the constants of C and R are selected so that the equation (1) has three real roots, the voltage between the main terminals can be attenuated without vibration in the circuit of FIG.

〔The invention's effect〕

As described above, the semiconductor circuit breaker of the present invention is a bidirectional energization type semiconductor circuit breaker in which a bridge rectification type snubber circuit and a nonlinear resistance element ZnO arrester are connected in parallel to one set of GTO thyristors combined in antiparallel. When the current is cut off, resonance oscillation that occurs between the parasitic capacitance of the ZnO arrester and the load inductance can be suppressed, and the system can be kept stable without disturbance.

In particular, in the series circuit of the capacitor and the resistor that attenuates the resonance vibration, the capacitor also has an effect of reducing the DC power capacity of the resistor R.

Further, the oscillation of the voltage between the anode and the cathode can be suppressed while the element after the GTO thyristor turn-off is still dynamic, and as a result, the element duty can be reduced and the element reliability can be improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the semiconductor breaker of the present invention, FIG. 2 is an operation waveform diagram of the circuit of FIG. 1, FIG. 3 is a basic equivalent circuit diagram of the circuit of FIG. 1, and FIG. Circuit diagram showing a conventional example,
FIG. 5 is an operation waveform diagram of the same as above. 1 ... DC power supply 2 ... Forward GTO thyristor 3 ... Reverse GTO thyristor 4 ... Capacitor 5, 6, 7, 8 ... Tioode 9 ... ZnO arrester, 10, 11 ... Resistor 12 ... Discharge GTO thyristor 13 ... Load, 13a ... Inductance 14… Bridge rectification snubber circuit 15… ZnO arrester parasitic capacitance 16… Resistance, 17… Capacitor (a)… On signal, (b) Off signal (c)… Load current (d)… Main terminal a ₁ -a Voltage between _two

Claims (1)

[Claims] 1. A bidirectional energization type semiconductor cutoff in which a pair of gate turn-off thyristors combined in antiparallel are connected in parallel with a bridge rectification type snubber circuit composed of a diode and a capacitor and a voltage dependent nonlinear resistance element such as a ZnO arrester. In the switching device, a series circuit of a resistor and a capacitor for damping resonance oscillation occurring between the parasitic capacitance of the voltage-dependent nonlinear resistance element and the inductance of the load when the semiconductor breaker is cut off is connected in parallel to the voltage-dependent nonlinear resistance element. A semiconductor breaker characterized by being connected.