A Novel Unity Power Factor Hysteresis Current Control for SPMSM Using Switching Table

In this paper, a novel unity power factor (UPF) hysteresis current control method for surface-mounted permanent magnet synchronous motor (SPMSM) drive system is presented. The optimum voltage vectors, which are selected from a switching table according to the magnitude and phase of the stator current vector, are applying to the voltage source inverter (VSI). The UPF operation for SPMSM is achieved by maintaining the angle between the stator current vector and stator flux vector at 90°. Compared with traditional direct torque control (DTC), the proposed method eliminates the disadvantages of the actual stator flux and torque estimation without deterioration of the dynamic properties of DTC. The current regulator is realized by using the hysteresis controller and the switching table while the vector control (VC) employs complicated coordinate rotating transformation, PI controller, and pulse width modulation (PWM). So, the proposed structure and the algorithm are easier to implement comparing with VC. It has been found that with the proposed scheme SPMSM drive shows adequate dynamic torque performance and considerable torque ripple reduction.