Torque Ripple Suppression Synchronous Optimal PWM for IPMSMs by Reallocating Current Harmonics in Multiple Synchronous Reference Frame

Torque ripple suppression plays a crucial role in the electric drive systems of electric vehicles. This work proposes a torque ripple suppression method for interior permanent magnet synchronous machine (IPMSM) drive systems based on synchronous optimal pulse width modulation (SOPWM). Firstly, the relationship between current harmonics vectors and switching angles of SOPWM is derived in a multi-synchronous reference frame. Then, the torque and current harmonics balance equation is introduced. revealing that current harmonics on the d-axis have a smaller effect on torque ripple. A weighting coefficient μ is designed and incorporated in the optimization function to acquire the inverter switching angles. The method shifts the current harmonics on the q-axis to the d-axis, effectively suppressing torque ripple. The effectiveness of the proposed SOPWM method is validated through both simulation and experimental results.