Digital Simulation of a Dynamic Voltage Restorer System

The Dynamic Voltage Restorer (DVR), a custom power device, has been used to protect sensitive loads from the effect of voltage sags / swells on the distribution feeder. The DVR’s main function is to inject the difference in voltage to the power line and thus maintain the load side voltage at the optimum value. This paper presents themodeling and closed loop control aspects of the DVR system with an H bridge inverter working against voltage sags / swells by simulation. The power circuit of the DVR system with an H bridge inverter with the control techniques used for compensation is explained. The proposed DVR is modeled and simulated using MATLAB/ SIMULINKsoftware. The simulation results show that the control approach performs very effectively and yields excellent compensation for compensating voltage sags / swells.