Half Open-End Winding Topology Based Nine-Leg VSI for Asymmetrical Six-Phase PMSM Drives

This article presents a half open-end winding topology based nine-leg voltage source inverter (HONL-VSI) to drive an asymmetrical six-phase permanent magnet synchronous motor (ASP-PMSM). Meanwhile, three winding connection modes (WCMs) are proposed for different output requirements. First, topology features of HONL-VSIs with three WCMs are investigated, including the currents of different legs, linear modulation range, and zero-sequence loop. Besides, HONL-VSIs with three WCMs are compared with three existing topologies for ASP-PMSM drives, and the potential application scenarios of the three WCMs are discussed. Next, to drive the HONL-VSI, the corresponding PWM method is developed based on the relative leg potential, which can be implemented simply. Further, simulation and experiment results are obtained to verify the feasibility of the HONL-VSI for ASP-PMSM drives with three WCMs. It can be found that HONL-VSI has a lower power device count and competitive performance compared with the existing open-end winding topology based VSI. Besides, HONL-VSI can also be the fault-tolerant reconfiguration topology of open-end winding topology based VSI for ASP-PMSM drives.