基于四桥臂拓扑的永磁同步电机断相容错控制策略

This paper proposes a fault tolerant strategy based on four-leg voltage source inverter for the permanent magnet synchronous motor (PMSM) drives system to ensure safe and reliable operation in case of single-phase open circuit. Firstly, due to the relationship of the current and voltage of non-fault phase, the mathematical model of the three-phase four-leg topology is established, and the compensation current of non-fault phase is derived. Then, using the equivalent relationship between the phase compensation current and the zero-axis current, the zero-axis current reference control amount is calculated. Furthermore, in order to overcome the shortcomings of the traditional zero-axis voltage compensation strategy and improve the zero-axis current tracking performance, the design of the zero-axis current closed-loop internal model controller (IMC) based on the desired dynamic and static characteristics, so as to achieve high-precision zero-axis current tracking control. Finally, the simulation and experimental results show that compared with the traditional feed forward zero-axis voltage compensation strategy, the proposed fault tolerant strategy based on four-leg topology has better steady-state characteristics.