The Optimal Direct Torque Control Strategy for Open-Winding Permanent Magnet Synchronous Motor in Variable DC Voltage Conditions

This paper proposes a novel optimal direct torque control (DTC) strategy for open-winding permanent magnet synchronous machine(OW-PMSM) in variable DC bus voltage conditions due to the voltage characteristics of the battery in electric vehicle. On basis of the different voltage vectors selection, the asymmetric property of output torque is analyzed, then the optimized method of switching table with respect to the voltage ratio is given for the higher output torque performance of OW-PMSM with variable DC bus voltages. Simulations and experiments are implemented to verify the effectiveness and reliability of the proposed control strategy for OW-PMSM.