An Enhanced Grid-Tied Off-Board Electric Vehicle Charger With Improved Power Quality Using Unified Control Approach

This article introduces a multifunctional electric vehicle charger (EVC) equipped with innovative control methodologies. In the proposed configuration, the grid-side converter (GSC) is equipped with an adaptive model predictive direct power control (AMP-DPC) system and dual active bridge dc–dc bidirectional converter controlled by modified direct power control (MDPC). These control strategies are designed to improve the power quality (PQ) of power grid, simultaneously ensuring efficient electric vehicle (EV) charging. The AMP-DPC approach utilizes a second-order generalized integrator (SOGI) to generate synchronization templates specifically tailored for single-phase systems. This control framework optimizes the switching sequence by minimizing a cost function, and crucially, it operates without dependency on a weighting factor, thus adapting seamlessly to various modulation scenarios without additional configuration. The study explores the interplay between instantaneous power and inductance imbalance on the ac side, observing that inductance mismatch impacts reactive power. A quantitative formulation for reactive power due to inductance deviation is experimentally validated, with an estimation technique proposed to mitigate its effects. A comprehensive stability analysis of the system has been performed here to further check the robustness of the EVC. Designed for unity power factor (UPF) in both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operations, the EVC maintains low harmonic distortion during charging and discharging mode. Vehicle-to-load (V2L) mode provides a reliable UPS for home ac loads during power outages.

 Keywords: Bidirectional multifunctional electric vehicle charger, dual active bridge converter, isolated converter, power quality.