Robust current residual vector-based multi-tube open-circuit fault diagnosis of inverters

In response to the shortcomings of traditional fault diagnosis methods such as low detection efficiency and susceptibility to external interference, this paper proposes an open-circuit fault diagnosis method for motor drive systems based on the robust current residual vector (RCRV). First, the motor drive system, which is a hybrid system composed of discrete switching signals and continuous current states, and the output current mathematical model of the system are established. Second, different fault models are obtained based on the changes in the current state for single tube, double tube in the same phase, and double tube in the different phases. Then, the current is estimated according to the fault model, the ABC current is converted to d-q current, and the d-q residual is generated with an ideal current. When a fault occurs in the drive system, the d-q-RCRV between the estimator and the plant displays the characteristic amplitude and phase, achieving fault localization. Finally, simulation and experimental results show that the proposed method can detect various fault types efficiently, improving the reliability and robustness of the system under strong interference environments.