Torque ripples reduction in PM synchronous motor using frequency-domain iterative learning control

PM synchronous motor drives are widely used for high-performance industrial servo applications where torque smoothness is an essential requirement. However, parasitic torque pulsations exist in PMSM drive, which deteriorate the performance of PMSMs. In this paper, we propose a simple plug-in frequency-domain iterative learning control (FILC) scheme for generating a compensation reference current to improve the steady-state torque response. A torque observer is implemented to estimate the instantaneous motor torque, which is used as the feedback information for the proposed controller. Experimental results obtained demonstrate the effectiveness of the proposed control scheme in reducing torque ripples.