A multi-unit bidirectional inductive power transfer (BIPT) system is suitable as a wireless energy trading platform for electric vehicles (EVs). Phase synchronization technique is required to implement flexible power flow pattern of such system. Traditional method utilizes dedicated synchronization module, which will increase the complexity and the cost of system. This article proposed a multi-unit BIPT system with power-synchronization controlled subunits. The resemblance between the multi-unit BIPT system and the traditional power grid dominated by synchronous machines is revealed. A power-synchronization method is proposed for the multi-unit BIPT system, which can significantly reduce the complexity and the cost of system because neither extra coils nor extra high-speed, high-precision detection and conditioning circuits are required. Experimental verification is carried out to verify the grid-to-vehicle (G2V) and vehicle-to-grid (V2G) capability of the multi-unit BIPT system and the effectiveness of the proposed power-synchronization method.

bidirectional inductive power transfer (BIPT);multi-unit;synchronization;vehicle-to-grid (V2G)