Fault-tolerant control strategy of DTPP-MSM for torque performance optimisation based on Quasi-Z-source inverter

Dual-three-phase permanent magnet synchronous motor (DTP-PMSM) with one open-circuit phase will suffer from reduced peak torque and increased output torque fluctuations due to direct current (DC) bus voltage limitation. The paper puts forward a DTP-PMSM fault-tolerant control strategy based on Quasi-Z-source inverter (QZSI) to ensure that the electric drive system can deliver the rated torque and speed under one-phase-opening fault condition. First, the voltage utilization of the inverter DC bus voltage with one open-circuit phase of a dual-Y phase-shifted 30° PMSM is analyzed. Secondly, the mathematical model of bus voltage and peak torque is derived. Finally, a DTP-PMSM fault-tolerant control strategy based on QZSI is proposed, and its performance is analyzed using simulation work. The result shows that this control strategy can increase the peak torque of the one-phase open-circuit DTP-PMSM by 40%. Thus, the existing fault-tolerant control strategies can make the DTP-PMSM boost overload and ensure that the electric drive system can deliver the rated torque and speed under one-phase-opening fault condition.