Torque ripples and EMI noise minimization in PMSM using hybrid filter

In this paper, a new hybrid filter topology is proposed to reduce torque ripples, voltage harmonics and electromagnetic interference (EMI) noises in permanent magnet synchronous motor (PMSM) with direct torque hysteresis controllers. The filter topology consists of IGBT active filter (AF),LC filter in the primary side and trap filter in the secondary side of a coupling 1:1 transformer. The AF is characterized by detecting the harmonics in the motor phase voltages and uses hysteresis voltage control method to provide almost sinusoidal voltage to the motor windings. The active filter uses hysteresis voltage controller while the motor main circuit uses hysteresis direct torque control. The simulation results of this combined control structure show considerable torque ripples reduction in steady state range and adequate dynamic torque performance as well as considerable harmonics and EMI noise reduction.