Quasi Multirate Feedforward Current Control toward Nyquist Frequency of PWM for SPMSM

Abstract

A high-bandwidth current controller is necessary to suppress torque ripple. To drive motors at high speeds, the reference-value-tracking performance must be guaranteed. To ensure the reference-value-tracking performance around the Nyquist frequency, the proposed method samples reference values twice more than the conventional multirate feedforward control for a second-order system. We have previously proposed a current controller based on the perfect tracking control. However, there is still room to improve the reference value tracking performance; therefore, a new approach based on the quasi multirate feedforward current control has been proposed and applied to permanent magnet synchronous motors. The proposed method doubles the tracking points of the reference current waveform compared with the conventional methods. The enhancement of the proposed approach has been demonstrateted using simulations and experimental verifications.