Fault-tolerant operation for five-phase permanent magnet synchronous machine drives with five-phase six-leg inverter

Five-phase permanent magnet synchronous machine (PMSM) can operate under open-circuit faults with the appropriate current regulations. However, the traditional current regulations based on the five-phase half-bridge inverter have to satisfy the constraint of zero neutral point current, which limits the fault-tolerant performance of the machine. Thus, this paper investigates the current regulation based on the five-phase six-leg (FPSL) inverter, which relieves the zero-neutral point current limitation, and both current regulations considering the maximum torque (MT) and minimum copper loss (MC) are derived under different open-circuit conditions. The cost of the system has increased, but with the new regulations, better fault-tolerant operation capability of the machine can be obtained under all kinds of open-circuit faults. Moreover, with the introduction of the neutral point current, the machine can work under triple-phase open-circuit faults. In conclusion, the proposed control scheme based on the FPSL inverter expands the fault-tolerant operation capability of the five-phase PMSM. The experiment results prove the effectiveness of the proposed current regulation on increasing average torque or reducing copper loss under fault-tolerant operation. The five-phase six-leg inverter is adopted for the fault-tolerant control of the five-phase PMSM, which can relieve the constraint of the zero neutral point current and improve the performance of the machine. The maximum torqu MT and MC current regulations are considered under different open-circuit conditions, and their effectiveness are verified by the experiments. image