A CLOSED-LOOP OPERATION OF SUPER HIGH-SPEED RELUCTANCE MOTOR FOR QUICK TORQUE RESPONSE

There is increasing interest in using reluctance motors in super high-speed drives because of their robust mechanical characteristics and reduction in the rotor losses. The reluctance machine, which is the subject of this paper, is the revolving field air-gap flux synchronous machine, i.e., the unexcited salient-pole synchronous motor, but is not the doubly salient switched reluctance machine. The purposes of this paper are to examine the operating modes of the cageless reluctance motor and to propose a new control method for quick torque response. It is shown that the control of sinusoidal phase current in magnitude with fixed current phase angle provides a simple means for achieving quick torque response and efficient operation. The flux linkage, current, torque, and the rated voltage of the inverter are calculated for a reluctance motor. A performance comparison is made between the proposed control method and the field-oriented control method. Analysis and computer simulation show that substantial improvement in dynamic response and efficiency are achieved for a reluctance motor when operated with constant current phase angle compared with operation at constant direct axis current or constant flux. Test data are provided from a 24 000-r/min, 1.3-kW reluctance motor drive system.