A Modified Iterative Learning Controller for Reducing Torque Pulsations in Field Oriented Control Driven Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors are mostly used in low and high power and variable speed applications. Major disadvantage of PMSM is that the motor exhibits torque pulsations due to many factors from motor and drive. This paper proposes a modified iterative learning controller to reduce the pulsations in torque of permanent magnet synchronous motors (PMSM). Modified ILC has memory to store previous control actions and previous error. Proposed ILC scheme consists of previous and current loop gain in order to minimize the torque oscillations. Previous control actions are stored and used to reduce the steady state periodic torque pulsations. Space vector pulse width modulation is used to reduce the harmonic noise in motor current which in turn improves performance of drive. Torque error is calculated and the iqs ref current gets altered accordingly to minimize torque variations. The simulation of the PMSM drive with field oriented control and proposed controller is done using MATLAB 2009b. The results obtained shows better reduction of torque pulsation and improved performance over conventional methods.