Minimisation of Torque Ripple in PMSM Using a Proportional Resonant Control Technique

Abstract: Permanent magnet synchronous motors (PMSM) are extensively used in many applications including robotics, precision machining etc. because of their good features such as, high efficiency, light weight, better accuracy, and low maintenance requirements compared to induction motors. Because of the increasing demand for energy efficiency, PMSM replaces the traditional induction motors. The main problem with this motor is the formation of torque ripples at low-speed which may cause mechanical vibrations and induces oscillations in speed. So low-speed applications of this motor have some limitations. Vector controlled PMSM drives can be used to supply lesser torque ripples and better dynamic response. Conventionally Proportional integral (PI) controllers are used for this. But the performances of the PI controllers are affected by load disturbances, speed variations and parameter variations due to its constant proportional gain and integral time constant. The novelty of this work is implementing a new control technique by using a PI-resonant (PI-RES) controller by paralleling a variable frequency resonance controller with the conventional PI controller.

Keywords: Permanent magnet synchronous motors, Proportional integral (PI) controllers, PI-resonance (PI-RES) controllers, Torque ripples, Field oriented control