Implementation of discrete PWM control scheme on Dynamic Voltage Restorer for the mitigation of voltage sag /swell

A Dynamic Voltage Restorer (DVR) is one of the most common custom power devices to compensate for the voltage sag and swell. The main functions of the DVR are the injection of voltage to the power line and maintain the pre-sag voltage condition in the load side. Different control strategies are available depending upon the compensation technique. In this paper, a simple method for the generation of reference voltage for a DVR is presented. This control scheme provides superior performance compared to conventional control methods because it directly measurers the rms voltage at the load point without involving any transformation process. Even under system disturbances, this control scheme maintains a constant voltage at the load point. The control scheme is rather simple, flexible in cost and has an excellent voltage regulation capability. The simulation was carried using MATLAB/ SIMULINK and the results of the simulation show that this proposed method is able to provide the desirable power quality in the presence of a wide range of disturbances.