Open-circuit Fault Diagnosis and Fault-tolerant Control Strategy for Parallel Three-phase Rectifiers

In this paper, an open-circuit fault diagnosis and fault-tolerant control strategy for parallel three-phase rectifier are proposed. The different characteristics of three-phase rectifier under normal condition, single switch open-circuit fault and double switch open-circuit fault are analyzed in depth. A fault diagnosis method based on the harmonic content of the switching bridge arm is studied, and a method based on neural network is designed to analyze the harmonic content of the bridge arm to locate the fault switch of three-phase rectifier. The power quality characteristics of three-phase traction substation are analyzed, and a comprehensive compensation control strategy is proposed, which combines the positive sequence and negative sequence double closed-loop control with predictive current control. The correctness and effectiveness of the fault diagnosis method and integrated compensation control method are verified by simulation and experiment.