A Bidirectional Inductive Power Interface for Electric Vehicles in V2G Systems

TLDR

Demand for contactless power is rising, and inductive power transfer is a well‑recognized technique enabling contactless energy exchange. This paper proposes a novel bidirectional inductive power transfer system tailored for plug‑in electric vehicles and vehicle‑to‑grid applications. The system allows simultaneous, controlled charging or discharging of multiple EVs through loose magnetic coupling, with power flow governed by phase and magnitude modulation of converter voltages, as demonstrated by a 1.5‑kW prototype with a 4‑cm air gap. Experimental results show the interface delivers efficient, contactless integration of multiple hybrid or electric vehicles into standard power networks.

Abstract

Demand for supplying contactless or wireless power for various applications, ranging from low-power biomedical implants to high-power battery charging systems, is on the rise. Inductive power transfer (IPT) is a well recognized technique through which power can be transferred from one system to another with no physical contacts. This paper presents a novel bidirectional IPT system, which is particularly suitable for applications such as plug-in electric vehicles (EVs) and vehicle-to-grid (V2G) systems, where two-way power transfer is advantageous. The proposed IPT system facilitates simultaneous and controlled charging or discharging of multiple EVs through loose magnetic coupling and without any physical connections. A mathematical model is presented to show that both the amount and direction of power flow between EVs or multiple systems can be controlled through either phase or/and magnitude modulation of voltages generated by converters of each system. The validity of the concept is verified by theoretical analysis, simulations, and experimental results of a 1.5-kW prototype bidirectional IPT system with a 4-cm air gap. Results indicate that the proposed system is an ideal power interface for efficient and contactless integration of multiple hybrid or EVs into typical power networks.