A Universal EV Charging System with Extended Output Voltage Range for Future Electric Mobility

Abstract

The rapid diversification of electric vehicles and energy storage systems has created a need for universal battery chargers capable of supporting wide and evolving voltage standards. Present charging infrastructure is designed for fixed or narrow voltage ranges, leading to limited interoperability and reduced future readiness as battery voltages continue to increase. In this paper, a universal battery charger with a wide output voltage range of 100–900 V is proposed to address these challenges and enable future-proof charging solutions. The architecture integrates a bridge less power factor correction (PFC) converter, a full-bridge active power decoupling (APD) stage, and an LLC resonant converter with a voltage doubler circuit. Compared to conventional PFC topologies, the bridgeless PFC reduces conduction losses and ensures near-unity power factor with sinusoidal input current. To mitigate low-frequency second-harmonic power ripple without bulky electrolytic capacitors, the APD stage employs compact film capacitors, improving reliability, thermal performance, and lifetime. The LLC resonant converter, combined with a relay-controlled voltage doubler, enables flexible high-voltage operation while maintaining high efficiency. A 3.3 kW hardware prototype is implemented and experimentally validated, achieving a peak efficiency of 96.5%, demonstrating the feasibility of the proposed universal charger for next-generation wide-voltage battery charging applications.