| 摘要 |
<p>A protection arrangement for a switching device having a possible open-circuit failure condition comprises a thyristor (307) connected in parallel with the main current-carrying terminals of the switching device (101) to be protected, the thyristor being connected such that a forward current direction of the thyristor is the same as a direction of a current which flows between the main current-carrying terminals during normal operation of the switching device, and being arranged to present an irreversible effective short-circuit when its normal parameter ratings are exceeded. The protection arrangement is particularly suitable for insulated-gate bipolar transistors (IGBT's) and preferably employs a pressure-packaged asymmetrical thyristor (ASCR) as the protection thyristor. The ASCR should be selected to withstand the normal (snubber-limited) dV/dt of the voltage across the switching device. <IMAGE></p> |
