Power Quality Improvement using Dynamic Voltage Restorer on E -Z Source Inverter

The device used to phase out voltage sags and a swell in the distribution lines is the Dynamic Voltage Restorer (DVR). The DVR can restore the load voltage within few milliseconds by injecting series voltage which is actually missing voltage in to system through series connected booster transformer, when it is subjected to voltage sags. Generally DVR can be connected to grid through inverter topologies such as Voltage Source Inverter (VSI) or Current Source Inverter (CSI). Tradition inverters (VSI /CSI) suffers from problem of limited output voltage(below dc link voltage), limitation on switching of upper and lower switches simultaneously and filter is needed to give sinusoidal output. All these problems get eliminated if embedded EZ-source inverter is used. This paper presents control strategy for DVR based on EZ source inverter. It has been observed that switching losses and harmonics are reduced drastically.