Photovoltaic based dynamic voltage restorer with energy conservation capability using fuzzy logic controller

In this paper, a Photovoltaic based Dynamic Voltage Restorer (PV-DVR) is proposed to handle deep voltage sags, swells and outages on a low voltage single phase residential distribution system. It can recover sags up to 10%, swells up to 190% of its nominal value. Otherwise, it will operate as an Uninterruptable Power Supply (UPS) when the utility grid fails to supply. It is also designed to reduce the usage of utility power, which is generated from nuclear and thermal power stations. A series injection transformer is connected in series with the load when restoring voltage sag and swell and it is reconfigured into parallel connection using semiconductor switches when it is operating in UPS and power saver mode. The use of high step up dc-dc converter with high-voltage gain reduces the size and required power rating of the series injection transformer. It also improves the stability of the system. The Fuzzy Logic (FL) controller with two inputs maintains the load voltage by detecting the voltage variations through d-q transformation technique. Simulation results have proved the ability of the proposed DVR in mitigating the voltage sag, swell and outage in a low voltage single phase residential distribution system.