Implementation of a Droop Based Voltage Controller through an EV Charging Station in an Islanded Microgrid

Abstract

The rapidly depleting fossil fuels and growing needs for better efficiency and reliability of power supply in the present electrical network makes the concept of microgrids vitally important. Channelizing the elevation in the field of renewable energy sources (RESs) for the reformation of the existing power grids explain the essence of a microgrid. However, the variable nature of the renewable power produced is one of the prominent factors affecting the stability of the islanded microgrids. High incursions of RESs in islanded microgrids have raised many voltage issues in power systems. The voltage fluctuations owing to integration of RESs is a well identified phenomenon in microgrids. These fluctuations can be controlled through power electronics (PE) interfaces with energy storage systems (ESSs). However, installation of conventional ESS in microgrids is a costly affair. With recent developments in electric vehicles’ (EVs’) market and economic incentives provided by government, EVs have gained the potential to replace the traditional storage devices. This work proposes a microgrid, consisting of EVs to facilitate energy storage, as well as to provide voltage regulation support. A voltage controller based on active power/voltage, i.e., P/V droop characteristic has been modeled which regulate the voltage by injecting or drawing active power from the EVs charging station (CS). The desired active power regulation is achieved by controlling charging and discharging rates of EVs. Further, a control algorithm has been developed for optimal distribution of power among each EV, considering their individual charging/discharging requests. The suggested control scheme has been simulated and verified on a microgrid test system.