Thyristor turn-off system
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorMasahiko Akamatsu
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Abstract
A thyristor turn-off system comprising: a thyristor having at least an anode, a cathode and a gate; a first reverse-bias means for applying reverse-bias between said anode and said cathode of the thyristor; a second reverse-bias means for applying reverse-bias to said gate of the thryistor; means for applying reverse-bias to said gate of the thyristor by said second reverse-bias means during the time of or before or after the forward bias initiation time for shifting between said anode and said cathode of the thyristor from reverse-bias to forward bias; whereby a failure of turn-off of the thyristor is prevented by said gate reverse-bias at least after said forward bias initiation time.
Claims7
A high speed method of turning off a thyristor in the conducting state, said thyristor having at least an anode, a cathode and a gate, comprising the steps of:
- applying a reverse-bias between the anode and cathode of said thyristor;
- applying a reverse-bias to the gate of said thyristor;
- applying a forward-bias between the anode and cathode of said thyristor while continuing to apply the reverse-bias to the gate of said thyristor;
- and
- subsequently removing the reverse-bias from the gate of said thyristor.
A thyristor high speed turn-off system comprising:
- a thyristor having at least an anode, a cathode and a gate;
- first reverse-bias means for applying reverse-bias voltage between the anode and cathode of said thyristor;
- and
- second reverse-bias means for applying reverse-bias to the gate of said thyristor, said second reverse-bias means coupled to said first reverse-bias means and including means for integrating the reverse-bias voltage applied between the anode and cathode of said thyristor to apply the integrated voltage as reverse-bias to the gate.
A thyristor high speed turn-off system comprising:
- a thyristor having at least an anode, a cathode and a gate;
- a gate reverse-bias circuit including an inductive element and a diode serially connected across the gate and the cathode of said thyristor;
- and
- gate reverse-bias pulse generating means connected in parallel to said diode of said gate reverse-bias circuit for applying reverse-bias voltage pulses to the gate of said thyristor.
Dependencies are inferred from the claim text.