Online Switching Strategy Between Dual Three-Phase PMSM and Open-Winding PMSM

To make full use of the advantages of dual three-phase PMSM (DTP-PMSM) and three-phase open-winding PMSM (OW-PMSM), this paper proposed a novel typology of motor drive which can switch between dual three-phase (DTP) structure and three-phase open-winding (OW) structure online. On this basis, the basic control and fault-tolerant control are studied to explore the superiority of the proposed typology. Under healthy conditions, no adjustment is required for the modulation method of the proposed control scheme when switching between DTP mode and OW mode. By using two bidirectional thyristors, smooth switching between the two modes can be guaranteed. Besides, the power weight of two inverters can be adjusted by changing the current ratio in DTP mode and changing the voltage ratio in OW mode. For the fault-tolerant control, when an open-phase fault occurs, DTP mode will be used to provide sufficient dimensions of current control and the fault-tolerant scheme can be realized through current compensation without changing the control framework. When an open-switch fault or short-switch fault occurs, OW mode will be adopted to guarantee symmetrical phase currents, and the remaining healthy switches in the faulty inverter are fully used to share the loss of the healthy inverter. The experiment has been conducted to prove the feasibility and superiority of the proposed typology and control scheme.