Dynamic Voltage Restorer Based on Proportional-resonant Control

A novel double-loop feedback control strategy of DVR based on proportional-resonant control is proposed. Compared with the traditional proportional-integral (PI) controller, the proportional-resonant controller applied to the output compensation voltage control strategy of DVR, can achieve tracking with zero static error for the reference signals of compensation voltage. Based on frequency characteristic analysis of proportional-resonant controller, the feedback control system of DVR in discrete domain introducing control delay is analyzed. Analyses show that the current inner loop using a simple proportional control has reliable stability, and the proportional-resonant control acting on outer voltage loop ensure steady-state accuracy of the system, as well as certain anti-interference ability against load currents. The whole system can obtain high quality steady-state compensation accuracy and fast dynamic response. The simulation results illustrate the correctness of theoretical analysis and the validity of the proposed double-loop feedback control strategy.