Integrated High-Efficiency Charging and Power Conversion Architecture for Electric Vehicles: Design, Modeling, and Experimental Validation

This paper presents a comprehensive study and experimental validation of an integrated high-efficiency power architecture for electric vehicle (EV) applications. The proposed system simultaneously optimizes battery charging algorithms and onboard low-voltage DC-DC conversion. On the charging side, we evaluate three techniques Conventional Constant Current–Constant Voltage (CC–CV), Multistage Constant Current (MSCC), and MSCC with Reflex Charging using a 72-cell lithium-ion battery model. The MSCC + Reflex approach achieves a 38% reduction in charging time and 23% lower energy loss compared to CC–CV. On the conversion side, a three-phase interleaved LLC resonant converter is developed using GaN HEMTs and Switch-Controlled Capacitor (SCC) technology. This architecture enables soft-switching (ZVS/ZCS) and precise current balancing, while significantly improving power density. The 3.8 kW prototype delivers a peak efficiency of 96.5%, 95.8% full-load efficiency, and 3.0 kW/L power density outperforming state-of-the-art converters. Comprehensive theoretical modeling, simulation results, and hardware testing validate the superiority of the proposed solution, making it a strong candidate for future high-performance EV systems..