Design methodology for torque angle control of a non-linear vector controlled Variable Reluctance Synchronous Motor

Synchronous motor drives are now-a-days becoming an attractive alternative to DC and IM drives, especially in the high power, low speed range. Various types of control schemes have been suggested for variable speed AC drives fed from static power sources, such as field oriented control, employing vector control strategies, has become quite popular in recent years. When this scheme is applied to a synchronous motor, the motor always operates at a lagging power factor. In this work, for the speed control loop of an inverter-fed synchronous motor drive a generalized design strategy is suggested, in which, its inherent flexibility to generate the same torque for different combinations of currents, is exploited. With that one can achieve more general types of control schemes. Existing control schemes such as unity power factor control, torque angle control as well as field-oriented control etc. can be obtained as special cases for special types of synchronous motor such as permanent magnet and variable reluctance motors, however the details of permanent magnet motor is beyond the scope of this paper. The closed loop system for the Variable Reluctance Synchronous Motor is simulated using MATLAB. The performance figures of various cases such as unity power factor control, torque angle control and field oriented control can be obtained and verified through simulation for different power factors of the motor ranging from lagging to leading including unity