Topology and Hysteresis SVPWM Fault-Tolerant Control Strategy of the Novel Multilevel Inverter

Large number of power electronic devices will increase the volume of multilevel inverter and increase the probability of failure; on the other hand, more redundant switching states can be provided to improve the fault tolerance of the inverter. Reduced Device Count Multilevel Inverters (RDC-MLIs) have tried to minimize the number of power electronic devices, but failed to take into account the fault tolerance of the inverter. A novel multilevel inverter topology and its hysteresis SVPWM fault-tolerant control strategy are proposed. This method not only realizes the multilevel output of the inverter, but also realizes effective fault-tolerant control for single-switch open-circuit fault and large-number double-switch open-circuit fault of the system without reducing or slightly reducing the output performance of the system. It ensures the direct switching of the driving signal to the variable structure unit, and abandons the main switching device and backup switching device operating in the inverter, which not only reduces the difficulty of implementation, but also has high stability. Through simulation and experimental results, the reliability of the topology and fault-tolerant control strategy is effectively verified.