A Hybrid IPT System With High-Misalignment Tolerance and Inherent CC-CV Output Characteristics for EVs Charging Applications

Inductive power transfer (IPT) systems are appropriate for electric vehicles (EVs) charging applications because of the advantages of safety and convenience. However, due to the considerable influence of pad misalignment, improving misalignment tolerance is important for IPT systems. Besides, constant current (CC) and constant voltage (CV) output characteristics are usually required for EVs battery charging. Therefore, to fulfill both features, a hybrid IPT system implementing high misalignment tolerance with inherent CC-CV output is proposed for EVs charging applications in this article. Two coils connected reversely in series are applied on the transmitter side while two coils, respectively, compensated by a capacitor and an inductor-capacitor-capacitor are applied on the receiver side. Hence, without an extra dc-dc converter or complicated control strategy and corresponding circuits, CC-CV output can be naturally achieved with high misalignment tolerance, which obviously increases the system reliability. Besides, zero-voltage switching and zero-phase angle condition can be easily achieved. A 1-kW experimental prototype is built. The experimental results show that the fluctuations of the constant charging current and the constant charging voltage are less than 5% when the proposed system operates within the predetermined misalignment range.