A Novel Predictive Direct Torque Control Using an Optimized PWM Approach

This article presents a novel predictive direct torque control (DTC) scheme using an optimized pulsewidth modulation (PWM) and a dead-time compensation. In the proposed method, two effective voltage vectors are selected according to the predicted torque and flux errors based on zero-voltage vector. The back electromotive force and flux-torque coupling are also taken into consideration. The torque and flux variations per sampling period are predicted by the zero-voltage vector and the two effective voltage vectors. The switching period of the three voltage vectors (zero, first effective, and second effective) are determined by the torque and flux errors along with the predicted torque and flux variations that have been calculated in the previous step. To improve the prediction result, a dead-time compensation algorithm and a modified PWM switching scheme are adopted to reduce dead-time effect. The detailed implementation of the proposed control scheme is presented. The effectiveness of the proposed predictive DTC-PWM is verified by both simulation and experiments. The results are also compared with the conventional method.