Non - Sinusoidal Power Supply Technology Based on Space Vector PWM for Multiphase Variable Speed Drives

Compared to the conventional three-phase system, multi-phase system is more suitable for high-power applications. In this paper, a mathematical model of non-sinusoidal space voltage vector pulse width modulation (NSVPWM) is established, and it aims to improve DC bus voltage utilization and torque density. The inherent relationship between NSVPWM and harmonic injection pulse width modulation(PWM) is analyzed, and each d-q plane reference voltage vector selection is discussed. Taking a nine-phase concentrated-full-pitch-winding induction motor for example, experiment maintains the same maximum tooth and yoke flux densities. Torque density and motor efficiency are compared under output sinusoidal voltage space voltage vector PWM(SSVPWM) and NSVPWM control strategy, respectively. The experimental results show that NSVPWM control strategy proposed is suitable for heavy load conditions. Compared with SSVPWM, the output torque is increased by 7.1% and the motor efficiency is increased by about 0.55%.