Performance Improvement of PMSM Current Control using Gain Attenuation and Phase Delay Compensated LPF

Abstract : This paper applies a compensated low pass filter (LPF) to current measurements for permanent magnet synchronous motor (PMSM) drives. The noise limits the bandwidth of current controllers and has more adverse influences on control performances under the light load condition because of the low signal-to-noise ratio. In order to eliminate the noise sensitivity, this paper proposes a digital LPF with a compensator of gain attenuation and phase delay which are unacceptable in current information for PMSM drives. Characteristics of the proposed LPF are analyzed in comparison with the general LPFs. The compensated LPF is basically designed by the orthogonal property of the measured currents in the  stationary reference frame. In addition, an implementation issue of the proposed method is discussed. Experimental results using the proposed method show improvements of the current control performance from two perspectives, rapid step responses and reductions of harmonic distortion.