Extension of the operating region of an IPM motor utilizing series compensation

This paper investigates the possibility of extending the operating region of a PM motor constrained by a given power supply voltage by using an open-winding motor drive configuration. A second inverter with a floating capacitor can be controlled to provide reactive power to the motor. A control method for the new open-winding PM machine drive employing FACTS concepts is proposed. Simulation and experimental studies on a lab scale IPM machine are presented. The results show that the proposed method is able to considerably improve the power capability of the motor beyond its base speed.