Nine-Switch Current-Source Inverter-Fed Asymmetrical Six-Phase Machines Based on Vector Space Decomposition

This paper proposes to employ a nine-switch converter as a current-source inverter (CSI) to supply asymmetrical six-phase motors. To achieve a compact high-density power electronic converter, the nine-switch converter has attracted the attention of researchers as a reduced-switch count DC/AC converter for six-phase motors. This configuration not only reduces the number of power semiconductors but also removes bulky dc-link capacitor. In order to control the proposed nine-switch current-source inverter (NS-CSI) configuration, space vector modulation scheme based on vector space decomposition (VSD) is developed. This scheme operates the converter properly with minimal switching transitions while eliminating the unwanted asymmetry harmonics between the two three-phase sets in asymmetrical six-phase machines. The inverter and machine models are investigated and the simulation results based on a MATLAB/SIMULINK model of the system are presented.