关键词: 故障检测, 　容错控制, 　光伏逆变器, 　三电平, 　开路故障, 　电压空间矢量

Abstract: In order to improve the operation reliability of the three⁃level PV inverter, an open⁃circuit fault detection and a voltage space vector redundancy fault⁃tolerant control method based on the improved current flow path were proposed. First, based on the three⁃phase three⁃level PV topology structure, the circuit current flow path after the open⁃circuit fault of each partial power device was analyzed in detail, the fault detection could be carried out by the current size flowing through the clamping diode and the load, the switching state of the switching device, and the fault type could be classified by injecting the under⁃excitation reactive current in a short time. Then, the change of the voltage space vector of the inverter after the open⁃circuit fault of the power device in different positions was theoretically explored. And the fault⁃tolerant control was completed according to the distribution law of the voltage space vector after the inverter fault and the redundancy vector of the inverter. The proposed method was fast in fault detection and fault⁃tolerant control without additional hardware cost and complex calculation. Finally, a prototype with rated power of 10 kW was built to verify the effectiveness and reliability of the proposed method.

Key words: Fault detection, Fault?tolerant control, PV inverter, Three?level, Open?circuit fault, Voltage space vector