Multiple reference frame control of permanent magnet synchronous motor with non-sinusoidal back EMF using adaptive notch filter

Permanent magnet synchronous motors (PMSMs) are suitable options for high-performance applications due to their potential of high power density and torque smoothness. Nevertheless, there are some factors affecting this feature by producing unwanted pulsating torque. One of the causes of torque ripple is the presence of harmonic components in motor back EMF. This paper has presented a multiple reference frame (MRF) method improving torque characteristic in PMSM regarding non-sinusoidal back EMF. An adaptive notch filter (ANF) was used as a current estimator which can separate needed current components. Optimal current components, obtained from Lagrange multiplier method, were regulated through PI controllers which guaranteed the desired convergence. Cogging torque and rms current minimization were intended, too. Results were investigated through simulations in Matlab/Simulink environment.