DD298719A5 - CIRCUIT ARRANGEMENT FOR TURN OFF RELIEF WITH ENERGY SUPPLY FOR SWITCH-OFF CIRCUIT BREAKER ELEMENTS - Google Patents

Abstract

The invention relates to a circuit arrangement which can be used in power electronics, in particular in power converters with turn-off power switching devices. In this case, in an arrangement for energy recovery with a snubber diode and a Abschaltentlastungskondensator parallel to the capacitor, antiserial to Beschaltungsdiode another diode arranged, which leads to the fact that no parasitic Induktivitaeten caused unwanted current zero crossing occurs in the main valve. Fig. 1 {turn-off relief; Energierueckspeisung; switchable power switching device; Power converters; Diode; Main valve; parasitic inductance; Current zero; switching-off; Power electronics}

Description

embodiment

The invention will be described in more detail with reference to an embodiment. Show it

Fig. V. The basic circuit of the circuit arrangement according to the invention

Fig. 2: the circuit in a concrete Sfomr I ter circuit with EnergierücKspeisung

In FIG. 2, the energy stored in the circuit capacitors Cs ₁ and C ₅ 2 is fed back into the backup capacitor C _d . It is assumed that when regenerating the energy from C _S1 in C _d, the current from the circuit Cst-TI-Dsa-TR at time ti, when Csi is discharged, momentarily on the circuit Dsi-D. S2-TR over commuted. However, this only applies in the event that there are no parasitic inductances in the components and in the structure. In reality, the inductance concentrated in the circle T1-C _S iD _s , enforces a transfer of the capacitor C ₈ , and a "soft" overcommunication of the current from C _S | and T1 to Ds. By the transfer of C ₅ , forms an additional circuit Csi-Dsi-TI in which a current is driven against the load current flowing through T1 by the negative voltage on C _S i, which can lead to a current zero crossing in T1, which means that the main valve T1 is switched on again with additionally occurring switch-on losses required.

By additionally inserting the Diodö (n) D _H , (and D _n2 ), the overcommunication of the current from the circuit C ₅ I-TI D ₈ J-TR via the circuit D _R , -T 1 -D _S i-TR on the circle D _S iD _S2 -TR also "gently" but without recharging the capacitor Cs _{) f} as this is prevented by the inductance-poor clamped to Csi diode D _n , one by the in the circle C _S | - D _n , concentrated Inductance-related minor reloading of C _S i would also result in a return swing through D _n , and not over Dsi-T1.

Claims (1)

Circuit arrangement for switch-off relief with energy recovery for disconnectable
Leistungsschaltbauelemente with a parallel to the main valve series circuit of a Abschaltentlastungskondensator and a Beschaltungsdiode, characterized in that parallel to the Abschaltentlastungskondensator (C ₈ ) another diode (D _R ) antiseriell to
Beschaltungsdiode (D ₈ ) is located. For this 1 page drawings Field of application of the invention The invention relates to a circuit arrangement in the power electronics, in particular in power converters with
switchable power switching devices, application can be found. Characteristic of the known state of the art There are a variety of Ausschaltentfastungsbeschaltungen with recovery of the energy of the Beschaltungskondensators
in which a Beschaltungskondensator with a Beschaltungsdiode in series, parallel to the turn-off
Power switching device is connected (DE-OS 3526836, DE-OS 3608868, DE-PS 3714175, JP-PS 59-188373,
US-PS 4639850). The principle of the capacitor diode Boschaltung allows low parasitic inductances in the circuit and thus low losses in the power semiconductor device. Through the use of one of the many known feedback circuits, the discharge of the Beschaltungskondensators during dor conducting phase of the main valve in a further energy storage
(At least one) based circuit based, the efficiency of the overall circuit can be significantly increased. The disadvantage here is that the snubber capacitor after its discharge by its own parasitic inductance
is reloaded and thus stimulates vibrations that can lead to zero current in the main valve. When using GTO thyristors as main converter main valve, the time for such a current zero crossing will usually be after completion of the excessive gate switch-on pulse to the amplitude of the recovery current from the
Circuit condenser not to be too big. The consequence of this is that the resumption of the anode current subsequent to the current zero crossing leads to high turn-on energy losses in the main valve. Through the use of special, low-inductance capacitors, this influence is limited, but not
(Goldbrunner, Vetter: Capacitors for GTO Thyristors, Siemens Comp. 22 (1984) 8). Object of the invention The aim of the invention was, by a circuit measure that in the recovery of energy from the
Shunt relief capacitor caused increased turn-on power dissipation in the main valves of a
To reduce converter circuit. Explanation of the essence of the invention The invention had the object of specifying a circuit which in a power converter circuit the unwanted
Current zero crossing in the main valve, which occurs after the discharge of the Beschaltungskondensators eliminated. The effect should be ensured even with finite parasitic inductances in the circuit main valve Beschaltungskondensator.
According to the invention this object is achieved in that in a power converter circuit of the Abschaltentlastungskondensator for the main valve, such as a GTO thyristor, is bridged with an additional diode, which antiserial to
Wiring diode is connected. The shutdown relief is doing by a series circuit of a Beschaltungsdiode and a
Abschaltentlastungskondensator realized in parallel with the main valve, wherein the polarity of the Beschaltungsdiode is set such that its anode is connected to the anode of the main valve or its cathode connected to the cathode of the main valve. Parallel to the Abschaltentlastungskondensator now according to the invention an additional diode antiserial to Beschaltungsdiode in
Shutdown relief circuit. By this additional diode is a reloading of the discharge capacitor by parasitic inductances following its discharge and thus an undesirable current zero crossing of the main valve current
prevented.