Hybrid suppressor utilising Miller effect for suppressing arcs formed at contacts of electrical switch

摘要

The suppressor includes the capacitor (30) which adds to the dispersion capacitance of the IGBT (36) such that, in response to a current crossing it, the voltage across the combined capacitance produces a sufficiently increased charge at the trigger to put the IGBT in a conducting state. This occurs when the switch contacts move to a first position in which the collector-emitter junction find themselves at the contacts. The voltage across the capacitance at its limit just maintains the conducting state but the voltage across the terminals of the IGBT is sufficiently limited to prevent arcing across the contacts.