Fault-tolerant control of device sharing three-level inverter

Aiming at the problem that the existing fault-tolerant topologies of the ANPC three-level inverter have difficulty in handling multi-device fault among three phases and improving utilization rate of power device, the device sharing ANPC fault-tolerant topology was presented. The topology reconfiguration strategy was designed for different fault categories including single-device fault, double-device fault and multi-device fault among three phases, which can tolerate various complex failures without derating operation or with only a small reduction in output performance. Meanwhile, in order to solve the problem that the traditional offline fault-tolerant control algorithm has difficulty in handling unexpected faults, an adaptive fault-tolerant control algorithm based on combinatorial logic was proposed. The algorithm was designed to find the appropriate topology reconstruction scheme online based on the fault category and its position and generate the effective fault-tolerant switch state table. By combing the PWM fault-tolerant control scheme, the proposed algorithm can tolerate various switch faults in real time. Finally, both simulation results and experimental results indicate that the device sharing fault-tolerant topology maintain the output performance of the inverter in fault-tolerant operation with higher the utilization rate and lower redundancy cost. © 2021, Harbin University of Science and Technology Publication. All right reserved.