Robust Modified SOGI-Based Control Scheme for Grid-Connected Bidirectional Multifunctional Residential Solar EV Chargers

This work presents a solar PV fed bi-directional EV charger (PVBEVC) designed for residential applications to facilitate charging/discharging of EV battery and simultaneous power quality enhancement by compensating reactive and harmonic powers at the point of common coupling (PCC). To achieve effective harmonic compensation, the system employs a Modified Discrete Second-Order Generalized Integrator (MDSOGI) algorithm to enable high-precision extraction of the fundamental load-current component. Moreover, the grid synchronization is achieved using an MDSOGI-based Frequency Locked Loop (FLL) featuring superior DC-offset rejection, improved transient dynamics, and reduced computational burden. For managing bidirectional power flow during EV battery charging and discharging, a Dual Active Bridge converter (DABC) is utilized. Extended Phase Shift (EPS) modulation is applied to improve efficiency by suppressing backflow power and minimizing the circulating current on the battery-side converter. First, a detail analysis of various operating modes of the PVBEVC is presented focusing on its dual function of battery charging/discharging and power quality improvement feature with enhanced performance using MDSOGI algorithm and MDSOGI-based FLL. To validate the proposed system and its functionalities like harmonic and reactive power compensations, an experimental prototype is developed and tested under various operating modes to demonstrate its practical viability.