Delphi Technologies, Inc.

Aravind Sourirajan Bharadwaj

Thomas W Nehl

Fang Deng

Malakondaiah Naidu

A three region control strategy for a permanent magnet motor is presented. In a first control region, the permanent magnet motor is operated at, a 120&deg; conduction square wave mode at reduced phase current, and below a no-load speed. The motor phase current commutation causes eddy current losses in the rotor magnets and core which are insignificant due to the low phase currents and relatively low rotor speed. Meanwhile, the inverter switching losses are kept low as two switches are in use (on/off) for each current commutation during the 120&deg; conduction mode. In a second control region, the permanent magnet motor is operated at a 180&deg; conduction sinusoidal wave mode with high phase currents. The 180&deg; conduction sinusoidal wave mode minimizes the commutation loss. In a third control region, the permanent magnet motor is operated above its no-load speed or in a field weakening mode. At these higher speeds the slot ripple and commutation losses on the rotor increase, and the demagnetizing component of the armature reaction increases due to field weakening. Commutation losses are minimized through sinusoidal current operation. In the field weakening mode, the phase current conduction angle is set to 180&deg; and the phase currents become sinusoidal.

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Canton, MI, United States of America

Aravind Sourirajan Bharadwaj