Grid Connected PV Powered EV Charger with Enhanced Grid Power Quality

Abstract

This paper presents a solar photovoltaic (PV), grid-integrated multifunctional off-board bidirectional electric vehicle battery charger (EVBC) that charges the EV batteries and simultaneously improves the grid power quality (PQ). The EVBC is degined to operate in two operating modes, i.e., grid connected mode (GCM), and islanding mode (IM). In GCM, the EVBC controller facilitates the charging/ discharging of EV along with improving the point of common coupling (PCC) voltage and grid current PQ. To do so, the sinusoidal reference current is generated by using the active current component (ACC) of the load current and synchronizing voltage templates (SVT) estimated from grid volatge. This paper proposes a self tuning filter (STF) based control technique to extract ACC and SVT from residential load current and grid voltage, respectively. In IM, the EVBC controller maintains the energy balance by charging/ discharging the EV batteries in accordance with the availability of PV power. Moreover, in IM, the EVBC ensures an undisturbed supply to residential load by maintaining pure sinusoidal voltage at PCC. Furthermore, the EVBC controller adopts STF based phase error minimization technique to maintain a seamless transition from GCM to IM. A simulation model of the EVBC is developed in MATLAB-Simulink, and the proposed STF based control technique is implemented. The steady-state and transient performance of the EVBC with the proposed control technique is verified in GCM and IM operation.