Model predictive flux control for enhancing steady-state performance of permanent magnet synchronous motor

Abstract:

To suppress motor common-mode voltage while maintaining good steady-state performance,a model predictive flux control method was proposed. Firstly, the H8 inverter′s candidate voltage vectors are expanded by incorporating zero vectors into the candidate set to reduce the current harmonic content. Secondly, according to the flux error vector, the voltage vectors are rapidly selected, which ensures low torque ripple and low current harmonic content. Moreover, Considering the influence of dead-time (DT) on common-mode voltage, the action sequence of the selected voltage vectors is defined to avoid potential equivalent zero vectors. Then, based on the flux beat control principle, a new calculation method of voltage vector duty cycle is designed to reduce flux pulsations. Finally, the proposed control method is compared with the three-vector method, five-vector method and eight-vector method which can suppress the common-mode voltage. The results show that the proposed control method can avoid the dead-time common-mode voltage peak. Comparing with the three-vector method and the eight-vector method, the common-mode voltage amplitude is reduced by 66.67% and 33.33%, respectively. At the same time, the proposed control method can effectively reduce the torque ripple, flux ripple, and current harmonic content of the motor. The proposed control method can improve the steady-state performance of the motor while suppressing the common-mode voltage, and reducing the computational complexity.