Sensor fault diagnosis and tolerant control for single-phase two-level PWM rectifier based on fault estimation

Rectifier is a significant part of traction drive system, once it fails, it will be extremely detrimental to the operation safety of the electric locomotive. Therefore, this paper presents a fast fault diagnosis and tolerant control method of catenary current sensor and DC-link voltage sensor for singlephase two-level PWM rectifier. Firstly, a rectifier model subjected to sensor fault and perturbation is established, and an augmented descriptor system is constructed. Then, estimation of the original state vector and the sensor fault with perturbation is achieved simultaneously through a fault estimator. It is not necessary to pre-design threshold, which improves the diagnosis speed and system performance. Finally, the fault compensation technique is introduced to complete fault tolerant control. Simulation results are presented to validate the effectiveness and reliability of the proposed approach.