NEW ASYMMETRICAL MULTILEVEL INVERTER BASED DYNAMIC VOLTAGE RESTORER

Abstract

In this paper, a new topology for multilevel converter based on sub-multilevel converter units and full-bridge converters is proposed. The proposed topology significantly reduces the number of dc voltage sources and switches as the number of output voltage levels increases. To synthesize maximum levels at the output voltage and to reduce the total harmonic distortion (THD), three different control strategies are proposed. The operation and performance of the proposed multilevel converter have been analysed and simulated in the MATLAB software and the results are presented for single-phase 25-level converter. Dynamic Voltage Restorer is a power electronic device that is used to inject 3-phase voltage in series and in synchronism with the distribution feeder voltages in order to compensate voltage sag. The principle component of the DVR is a voltage source inverter that generates three phase voltage and provides the voltage support to a sensitive load during voltage sags. The improved version of proposed multilevel inverter with reduced THD is used in DVR to compensate the voltage sag in power system and if any fault occurs in power system thereby reduce the voltage variation in distribution side. Simulation of DVR has been developed by using Matlab/Simulink.