Different control schemes for power quality improvement using embedded Z source based Dynamic Voltage Restorer

There is a need for instant mitigation of voltage sag/swell to maintain the load voltage constant since voltage sag and swell is most common problem customers are facing repeatedly. To restore the voltage sag induced due to fault or sudden load imposed on the system, the device is used to mitigate voltage dynamically is called “Dynamic Voltage Restorer.” Generally DVR is connected to grid through Voltage Source Inverter (VSI) or Current Source Inverter (CSI) which has certain demerits like problem of limited output voltage (below dc link voltage), restriction on switching of upper and lower switches simultaneously and requirement of filter to give sinusoidal output. All these complications get discarded if embedded EZ-source inverter is used. This paper presents two different control strategies for DVR based on EZ source inverter such as SRF (feed forward) control technique and PQ theory for series compensation along with its MATLAB simulation and results. The result shows the comparison between these two control strategies.