Integrated current regulation for a brushless ECM drive

An enhanced means of regulating phase currents in a brushless electronically commutated motor (ECM), without the use of any discrete current sensors, such as shunts or current transformers, is described. Current feedback information is provided by current sensors integrated into MOS-gated power switches (MOSFETs and IGBTs), and the current regulation is performed by gate drive power integrated circuits. A high degree of drive circuit integration is achieved with this scheme, in addition to providing protection against dangerous fault currents not sensed by conventional bus-shunt configurations. Available power semiconductor switches and power integrated circuits make this technique applicable to permanent magnet ECM drives operating at bus supply voltages up to 500 VDC with power ratings from fractional to >10 hp.>