Compound passive filter to minimize torque ripples and EMI noises in PMSM drives

This paper proposes a compound passive filter topology to reduce torque ripples and harmonic noises in permanent magnet synchronous motor (PMSM) derived by field oriented control. The compound filter has two tuning frequency setting points, one at inverter switching frequency and the other at some average selected frequency. The filter topology is characterized by affecting inverter switching frequency in such a way to decrease stress on switching elements. The filter topology uses series dissipative elements to reshape motor voltage waveform to provide semi-sinusoidal voltage to the motor windings. The simulation results show that the proposed topology is effectively reduces torque ripples as well as total harmonic distortion (THD) and electromagnetic interference (EMI) noise level.