Implementation of Coordinated Control and Power Flow Management Strategy for a Solar Powered EV Charging System

Rapid growth in electric vehicle (EV) adoption worldwide has created an urgent demand for smart, cost-effective, and renewable-integrated charging infrastructure. Conventional grid-only chargers are limited by unidirectional power flow and dependence on fossil-fuel-based electricity, motivating the integration of solar photovoltaic (PV) sources. This paper presents a smart hybrid EV charging system that combines a solar PV source with utility grid power, controlled by an ESP32 microcontroller with real-time OLED feedback. The proposed controller dynamically identifies seven operating modes — including PV-only, grid charging, hybrid, vehicle-to-grid (V2G), PV export, auto-switching, and fault protection — based on real-time voltage and current sensing at 500ms intervals. The hardware architecture employs a Power Factor Correction (PFC) boost stage, a Perturb and Observe MPPT-controlled boost converter, and a phase-shifted full-bridge (PSFB) DC-DC converter enabling high-efficiency bidirectional power transfer with galvanic isolation. The control logic is described through pseudocode and a mode-selection flowchart. Prototype testing on a 100 W PV panel and 48 V/20 Ah Li-ion battery demonstrates stable DC-link regulation at 400 V, near-unity power factor (PF ≈ 0.98), total harmonic distortion below 4%, mode transition within 50ms, and overall system efficiency of approximately 94.8% under rated conditions. The proposed design is cost-effective and well-suited for residential and small commercial EV charging applications.