Voltage sag/swell compensation using Z-Source inverter based dynamic voltage restorer

This paper presents the modeling and simulation of a dynamic voltage restorer as a voltage sag/swell mitigation device in electrical power distribution networks. The dynamic voltage restorer, with its excellent dynamic capabilities, when installed between the supply and a critical load feeder, can compensate for voltage sags/swells, restoring line voltage to its nominal value within few milliseconds and hence avoiding any power disruption to the load. A new topology based on Z-source inverter is presented in order to enhance the voltage restoration property of dynamic voltage restorer. Z-source inverter would ensure a constant DC voltage across the DC-link during the process of voltage compensation. The modeling of Z-source based dynamic voltage restorer is carried out component wise and their performances are analyzed using MATLAB software. The simulation results shows that the control technique is very effective and yields excellent compensation for voltage sag/swell mitigation.