Robust current control of single-phase PWM rectifier based on generalized internal model control

Faults in traction system rectifiers can cause deterioration in system performance, robustness, and continuity. A single fault may propagate and cause the whole system to be shut down. Therefore, improving the robust stability and reliability of the control system is becoming more important. This study presents a robust current control based on a generalized internal model control (GIMC) for single-phase pulse width modulation (PWM) rectifier. The study aims to simultaneously achieve decent dynamic performance and robustness for the rectifiers under current sensor gain faults using generalized internal model control. H_∞ loop shaping can maintain robustness and achieve acceptable performance for the system in such cases. However, this controller will be conservative during an increase of sensor gain faults. That is, we sacrifice performance for robustness. Therefore, the GIMC structure is proposed to balance robustness and dynamic performance in such cases. The proposed control scheme during sensor gain faults is investigated. Furthermore, the robustness is analyzed using the ν -gap metric. The proposed GIMC control framework consists of two parts, nominal and robustness controllers. The system is controlled solely by the nominal controller in normal operation in the absence of current sensor gain faults. If they occur, then the robustness controller will be active to maintain system robustness and achieve acceptable performance. The nominal controller is chosen as H_∞ loop shaping to assure nominal performance, while the robustness controller is chosen as the plant inverse cascaded by low pass filter to compensate for the sensor gain faults. Hardware-in-loop experimental results indicate that the suggested fault-tolerant control achieves good performance and robustness in comparison to the H_∞ loop shaping controller.