Current control method of six-phase PMSM drive system with parallel back-to-back converters

This paper proposes a novel vector space decomposition (VSD) current control method for six phase asymmetrical permanent magnet synchronous motor (PMSM) with two sets of two three phase windings spatially shifted by 30 electrical degrees, which supplied by the parallel back-to-back converters. Due to the influence of the non-sinusoidal back electromotive force of PMSM and the inverter non-linearity, this will generate large 5th and 7th current harmonics. To solve these problems, the principle analysis of the 5th and 7th current harmonics compensation is presented in detail, and an improved VSD current control scheme based on PI and resonant regulator is proposed to suppress current harmonics. The effectiveness and the analytical development of the proposed strategy are proved by a complete set of simulation results.