The SVPWM strategy in full modulation region for dual three-phase PMSM

For shift 30 degree dual three-phase motor which is fed with six-phase voltage source inverter, a novel space vector pulse width modulation (SVPWM) strategy in full modulation region is proposed. The proposed strategy is able to increase the utilization ratio of the DC bus voltage and eliminate the system losses and torque ripple. According to the value of modulation index, the modulation range is divided into linear modulation region and overmodulation region. In linear modulation region, the modulation algorithm in sinusoidal modulation region and non-sinusoidal modulation region is unified into an algorithm based on the intermediate vector. This algorithm is simple and able to decrease the harmonics of 6 k±1(k=1,3,5, …) injected in the non-sinusoidal modulation region greatly. In overmodulation region, the overmodulation algorithm in three-phase system is extended to the six-phase system and improved; through the improved algorithm, the amplitude of reference voltage is proportional to the modulation index in overmodulation I region, which makes the algorithm be implemented easily; the distortion of the phase voltage is reduced through the phase correction in overmodulation II region. Simulation analysis and experimental results demonstrate the effectiveness and feasibility of the proposed strategy.