Grid voltage sensor fault‐tolerant control for single‐phase two‐level PWM rectifier

Abstract

Abstract The main purpose of this work is to address the problem of robust grid voltage sensor fault‐tolerant control for a single‐phase two‐level rectifier. First, considering a rectifier with disturbances and grid voltage sensor fault, the standard switched system model is constructed. Based on identical transformation, the original system is converted into an augmented system. In the augmented system, the information of the grid voltage sensor fault is included in the state vector. Second, an unknown input observer is designed for the augmented system for sensor fault estimation. The observer error is totally robust against independent deterministic disturbances. In addition, the effect of the disturbance caused by unknown disturbances or a modelling error is minimised with respect to a prescribed H∞ performance index. Finally, the sensor fault‐tolerant control is realised by fault compensation technique, which protects the rectifier from serious performance degradation in the presence of the grid voltage sensor fault. The proposed fault‐tolerant control strategy requires no supplementary hardware and all the inputs involved in the algorithm are directly available. Simulation and experimental results are exhibited to illustrate the capability of the proposed method to tolerate the grid voltage sensor fault.

Keywords

• PWM rectifiers
• control system synthesis
• electric current control
• observers
• power grids
• sensors