Sensor-Fault-Estimation-Based Tolerant Control for Single-Phase Two-Level PWM Rectifier in Electric Traction System

This article presents a fault-estimation-based tolerant control strategy for single-phase two-level pulsewidth modulation rectifier subjected to catenary current sensor fault and dc-link voltage sensor fault. First, an augmented descriptor system is developed for the rectifier, whose augmented state vector consists of the state vector of original system as well as the sensor fault together with the measurement disturbance. Then, a linear reduced-order observer is designed for the descriptor plant. Accurate asymptotic estimation of the original state vector and the disturbed sensor fault are thus achieved simultaneously. Finally, the fault tolerant design method is addressed through sensor fault compensation, which allows the pre-design controller to continue to function normally even when both catenary current sensor and dc-link voltage sensor are faulty. Simulation and hardware-in-the-loop test results confirm the effectiveness of the proposed method.