Torque Ripple Reduction in Permanent Magnet Synchronous Motor using Fuzzy Logic Control

Permanent Magnet Synchronous Motor (PMSM) drives are widely used in applications where smooth torque is required. However, the main disadvantage of PMSM is torque ripple that leads to mechanical vibration and acoustic noise. For applications that require precise tracking, the machine should be free of torque ripples. Vector controlled PMSM drive provides better dynamic response and lesser torque ripples, and necessitates only a constant switching frequency. The outer loop in vector control greatly affects the system performance. Proportional plus integral (PI) controllers are usually preferred, but due to its fixed proportional gain and integral time constant, the performance of the PI controllers are affected by parameter variations, load disturbances and speed variations. These problems can be overcome by the fuzzy logic controllers, which do not require any mathematical model and are based on the linguistic rules obtained from the experience of the system operator. This paper describes two new instantaneous torque control schemes 1) Fuzzy Logic Controller (FLC) with Hysteresis Pulse Width Modulation (HPWM) 2) Fuzzy Logic Controller (FLC) with Space vector Pulse Width Modulation (SVPWM) respectively to reduce torque ripples in PMSM driven by Field oriented control. The design, analysis and simulation of the proposed system is done using MATLAB version R2009a and the simulation results are discussed.