Abstract
Dynamic voltage restorer (DVR) is a power electronics based custom power device (CPD) which is used in distribution system to mitigate voltage sag problem, although the performance of DVR depends mainly on its control technique. In this paper, a synchronous reference frame (SRF) theory based versatile control technique is presented for DVR to mitigate voltage sag problem for sensitive loads in distribution system. The DVR is connected with the load bus in series through injection transformer and filter combination. To improve sag detection in DVR a fuzzy logic based automatic switch is introduced. Proposed control technique has capability to settle balanced as well as imbalanced sag. An efficient strategy to regulate DC link capacitor voltage of DVR is also presented in this paper. Performance of DVR with the proposed control technique is evaluated using Matlab/Simulink. Simulation results show the effectiveness of proposed control technique for DVR to settle voltage sag.