DESIGN AND DEVELOPMENT OF GRID-INTERACTIVE ELECTRIC VEHICLE CHARGER

Abstract

Electric vehicles (EVs), with their increasing penetration into the power grid, present a significant opportunity to support grid reliability by functioning as distributed energy resources rather than passive loads. On average, an EV remains plugged in and available for energy interaction for approximately 22 hours per day, providing a unique chance to utilize its battery for valley filling, load shifting, and grid de-stressing. Smart chargers can dynamically synchronize with the grid, discharging power during peak demand periods and recharging during low-demand or surplus-generation periods. By aggregating multiple EVs across the network, this approach reduces strain on conventional generation units and transmission infrastructure while promoting a more balanced and flexible grid operation. The intelligent orchestration of these charging events contributes to frequency stability, defers network upgrades, and improves the overall operational economy of the power system. This work develops an advanced control strategy for bidirectional EV chargers, enabling them to support both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operations while enhancing grid stability, power quality, and distributed flexibility. The control framework leverages the Cascaded Non-Identical Second-Order Generalized Integrator (CNISOGI) a high-selectivity fourth-order quadrature signal generator to extract highly accurate unit vector templates and fundamental components of grid and load currents under conditions of unbalance, harmonics, and dynamic voltage events such as sags and swells. These extracted signals serve as reference inputs to a synchronous reference frame-based current controller, which governs the charging converter. The controller is further augmented to provide dynamic reactive power compensation at the Point of Common Coupling (PCC), reducing the burden on the utility by handling the var requirements of nonlinear residential and emergency loads. This results in unity power factor operation at the interface, minimizing transmission losses and supporting grid voltage profiles.