Research on Optimization SVPWM Method of Nine-switch Inverter for Bearingless Motor Based on Reducing Switching Times

Abstract

Abstract The traditional bearingless motor system controlled by two three-phase inverters has a high cost and volume. In this paper, the nine-switch converter is applied to the bearingless motor control system, which can control the torque winding and suspension winding of the bearingless motor at the same time to save three MOSFETs. This paper proposes a nine-switch inverter SVPWM method to reduce switching loss. This method is no longer limited to only considering the action sequence of voltage vectors but reduces the switching number from selecting voltage vectors. The optimal nine-switch inverter basic voltage vector selection principle is determined by comparing the switching times of each sector combination with different voltage vector combinations. Finally, the simulation results verify the effectiveness of this method.