A Robust Control Scheme for Dynamic Voltage Restorer with Current Limiting Capability

In this paper, a second order sliding mode control scheme is utilized for outer voltage loop of a three-phase fault current limiter-based dynamic voltage restorer (FCL-DVR) instead of a conventional proportional integral/proportional resonance (PI/PR) controller. The new control strategy improves the dynamic performance of the FCL-DVR against voltage distortion. Furthermore, by using the proposed robustness controller, the FCL-DVR can smoothly switch between the FCL and DVR operation modes. Compared with other existing control schemes, the proposed control strategy for the FCL mode can still work well under a large fault current. The MATLAB/Simulink simulation results demonstrate that the proposed control strategy is robust to voltage harmonics, sag and swell. They also show that the proposed control scheme can effectively limit the fault current in different scenarios.