Patent ID: 8125747

Claim:
A drive system for a multi-phase electric machine with a permanent magnet rotor, the drive system comprising: conduction paths for each phase; detectors on each of the conduction paths for determining electrical condition of the conduction path; at least one selectable interconnection path between all of the conduction paths; and at least one selectable interconnection path being operable to connect all of the conduction paths together responsively to at least one of the detectors determining that the electrical condition of its respective conduction path is representative of a predetermined electrical fault condition, so that heating of the rotor during continued rotation of the rotor is prevented; and a current controller including: solid-state switches interconnected to comprise the selectable interconnection path between all of the conduction paths; a processor for providing gating signals for normal operating control of the electric machine in an absence of the predetermined electrical fault condition; and a switch controller for monitoring the detectors and producing gating signals to the solid-state switches to produce the selectable interconnection path with the solid-state switches, wherein the switch controller operates independently from any software of the processor.