Voltage vector selection strategy of permanent magnet synchronous motor direct torque control system

The basic control principle of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) is to select the proper voltage vector to satisfy control demands of the amplitude of stator flux and torque. It is hysteresis control in nature. Voltage vector selection strategy as the hysteresis control principle determines control performance of system. In this paper, effects of voltage vector on the amplitude of stator flux, toque angle, excitation torque, reluctance torque and torque in PMSM DTC system are analyzed. Simplified expressions are given to express control principles of these variables are given and voltage vector selection area is proposed. Finally, a simply way to determine voltage selection area is given.