SCHUTZSCHALTUNG FUER EINE FAHRMOTOR-ANSTEUERVORRICHTUNG

摘要

A traction motor drive protection circuit which provides the inverter protection capability of a conventional commutation arrangement, but which limits or eliminates fault currents that stress the internal elements of the alternator and traction machines. A series protection thyristor is connected between a commutation thyristor and the inverter circuit to block motor fault currents, and RC elements are connected in series with the commutation thyristor to limit alternator fault currents. Normal inverter gating is continued in the presence of a fault, to circulate the stored inductive energy and discharge the filter capacitor, providing a "ride-through" operation which is substantially transparent to the traction motor. The RC elements in the commutation circuit not only limit the alternator faul current, and hence the stress on the eommutation thyristor, but also commutate the commutation thyristor to provide automatic reset capability.