Quasi-resonant thyristor current interrupter
AssigneeABB Schweiz AG
InventorsXiaoqing Song, Yu Du, Yuzhi Zhang, Harshang Shah
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Abstract
In one aspect, a quasi-resonant turn-off circuit is provided. The quasi-resonant turn-off circuit is couplable in parallel with a pair of anti-parallel thyristors. The quasi-resonant turn-off circuit includes a resonant capacitor and an energy recovery circuit. The resonant capacitor is configured to supply a charge to the pair of anti-parallel thyristors to decrease a turn-off time of the pair of anti-parallel thyristors. The energy recovery circuit is configured to recharge the resonant capacitor using remnant energy left in parasitic inductances coupled to the quasi-resonant turn-off circuit after the pair of anti-parallel thyristors is off.
Claims20
A quasi-resonant turn-off circuit couplable in parallel with a pair of anti-parallel thyristors, wherein the quasi-resonant turn-off circuit comprises:
- a resonant capacitor configured to supply a charge to the pair of anti-parallel thyristors to decrease a turn-off time of the pair of anti-parallel thyristors;
- and
- an energy recovery circuit configured to recharge the resonant capacitor using remnant energy left in parasitic inductances coupled to the quasi-resonant turn-off circuit after the pair of anti-parallel thyristors is off.
A solid-state switching apparatus, comprising:
- a pair of anti-parallel thyristors configured to selectively couple a source with a load to conduct a load current;
- and
- a quasi-resonant turn-off circuit coupled in parallel with the pair of anti-parallel thyristors, wherein the quasi-resonant turn-off circuit comprises:
- a resonant capacitor configured to supply a negative bias voltage to the pair of anti-parallel thyristors and commutate the load current from the pair of anti-parallel thyristors to the quasi-resonant turn-off circuit;
- and
- an energy recovery circuit configured to recharge the resonant capacitor using a decay current generated based on parasitic inductances coupled between the solid-state switching apparatus and the load after the pair of anti-parallel thyristors is off.
A solid-state switching apparatus, comprising:
- a thyristor that selectively couples a source with a load to conduct a load current;
- a quasi-resonant turn-off circuit coupled in parallel with the thyristor, wherein the quasi-resonant turn-off circuit comprises:
- a resonant capacitor configured to supply a negative bias to the thyristor and commutate the load current away from the thyristor to the quasi-resonant turn-off circuit to interrupt the load current;
- and
- an energy recovery circuit configured to recharge the resonant capacitor using remnant energy left in parasitic inductances coupled between the solid-state switching apparatus and the load after the thyristor is off.
Dependencies are inferred from the claim text.