Design of a single inductor bidirectional DC converter for V2V energy transfer: On board charger architecture

Abstract

This paper presents a Single-Inductor Bidirectional Converter (SIBC) for unified onboard Electric Vehicle (EV) charging, integrating grid, battery, and wireless ports within a single power stage. The topology enables native Grid-to-Vehicle (G2V), Wireless-to-Vehicle (W2V), and Vehicle-to-Wireless (V2W) operation without hardware reconfiguration, eliminating cascaded converter-inverter structures. Non-ideal steady-state and small-signal models are developed, revealing mode-dependent dynamics including a right-half-plane zero in V2W mode that constrains bandwidth. A two-loop Average Current-Mode Control (ACMC) is proposed to mitigate this limitation, achieving 40× bandwidth improvement over conventional voltage-mode control. Parametric sensitivity analysis of inductor equivalent series resistance establishes quantitative design boundaries for sustaining conversion efficiency above 90%. Scalability assessment to 3 kW operation demonstrates compatibility with silicon carbide devices and a bridgeless totem-pole PFC front-end achieving THD less than 4% and power factor higher than 0.99, satisfying IEC 61000-3-2 Class A with higher than 35 dB ripple rejection at the battery terminals. Experimental validation using a 136 W prototype achieves 93.4% transmitter and 95.07% receiver DC-DC efficiency, with an overall end-to-end efficiency of 75.03% including an 84.5% wireless link. A 1 kW interim hardware test confirms scalable operation, while simulation validates CC-CV battery charging compatibility. The results demonstrate that the SIBC architecture is not the dominant source of system losses and provides a compact, scalable foundation for advanced bidirectional EV charging systems.