AFF-SOGI-DRC Control of Renewable Energy Based Grid Interactive Charging Station for EV With Power Quality Improvement

Abstract

In this article, a control of solar photovoltaic (PV) array, and wind energy conversion system (WECS) based charging station using an adaptive frequency-fixed second-order generalized integrator with dc offset rejection capability (AFF-SOGI-DRC), is presented for charging the electric vehicles (EVs) and improving the power quality of the grid. In comparison to SOGI-based algorithm, wherein a frequency feedback loop reduces the stability margin and FF-SOGI-based algorithm, where a double frequency oscillation and offset error constraint the algorithm capability, the presented algorithm precisely estimates the fundamental EV current. Moreover, the AFF-SOGI-DRC-based positive sequence extractor helps in generating the sinusoidal in-quadrature unit vectors under distorted and unbalanced grid voltages; therefore, the reference grid currents become harmonic free. The charging station is operated in the grid-connected mode (GCM) and an islanded mode (IM) to utilize the renewable energy maximally. The control of the charging station also includes the voltage synchronizing strategy that ensures the smooth transition between the GCM and IM. Moreover, a unified controller is designed to achieve four-quadrant operation vehicle to grid/grid to vehicle (V2G/G2V), vehicle to home power transfer, reactive power compensation, and active filtering, etc. The operation of the charging station complies with the IEEE 1547 standard, and the operation of the charging station is validated through the laboratory prototype.