Model Predictive Direct Torque Control of Surface PMSM System Based on Basic Voltage Vector of VSI

Abstract

In this paper model predictive direct torque control (MP-DTC) for surface permanent magnet synchronous motor (PMSM) direct torque control (DTC) system is proposed. Based on flux and torque's expressions of surface PMSM in stator flux reference frame, 6 basic voltage vectors generated by voltage source inverter (VSI) are used as candidate voltage vectors. And according to values of stator flux and torque at next sampling point after applying these 6 voltage vector, 6 different values of cost function about stator flux and torque's error are obtained. The predictive control will select voltage vector corresponding to the minimum cost function as output voltage vector. And in order to reduce the computational burden, based on the utilization rate of 6 voltage vectors, the predictive control using simplified aggregate of candidate voltage vectors is given. Simulation results show compared with switching table, control performance of predictive control is better. And compared with predictive control using 6 basic voltage vectors, the proposed predictive control has almost the same control performance, but switching frequency is decreased and calculation burden is also reduced.