A NEW CONTROL SCHEME FOR IMPROVING DISTURBANCE REJECTION IN SPEED CONTROL OF PERMANENT-MAGNET SYNCHRONOUS MOTORS

The major hurdle encountered in achieving high performance in servo sp eed control is the occurrence of large relative errors at low speeds d ue to torque variations. In this: paper, it is shown that this problem can be tackled in the case of synchronous motors, by keeping the stat or current and the rotor flux nonorthogonal and including an inner pos ition control loop to improve the transient behavior of the system. Su ch a scheme substantially improves disturbance rejection at the cost o f accentuating the nonlinearities of the system and increasing the cop per losses. In view of the pronounced nonlinearities encountered here, adaptive control using neural networks is resorted to.