A Novel Modified DTC-SVM Method with Better Overload-capability for Permanent Magnet Synchronous Motor Servo Drives

Abstract

Direct torque control with space vector modulation (DTC-SVM) is one of the most promising alternatives of field-oriented control in the case of permanent magnet synchronous motor drives. This method controls the electromagnetic torque of the motor with excellent dynamics which makes it an attractive choice in the case of servo drives. In this article DTC-SVM is investigated with Matlab-Simulink simulation and it is proven that DTC-SVM has severe instability-issues during overloading and its overload-capabilities are heavily dependent on the speed. Therefore, a novel modified DTC-SVM method is proposed which is stable during overloading and its overload-capabilities are practically independent of the speed. Also, the overload-capability of the new method is superior to that of classical DTC-SVM, while the two methods are practically identical from the point of view of the torque-control dynamics and the torque-ripple generated.