Single-Phase Zero Reactive Power Wireless Power Transfer Topologies Based on Boucherot Bridge Circuit Concept

High reliability and cost effectiveness of power electronic components have resulted in high level of interest in wireless power transfer techniques among academic and industrial professionals. Since the major interest is directed toward automotive and rail industries for electromagnetically coupled fast battery charging systems, a special transformer with a large gap and relatively large leakage inductance is used. To achieve desired voltage and power levels with a reasonable compact-sized transformer, high frequencies in the order of 20-100 kHz are preferred, producing high levels of reactive power, which limit the amount of transferred power and efficiency if not compensated. There are four basic transformer compensation topologies reported in the literature, each being the combination of series and/or parallel compensations. This paper presents all four topologies and the associated input-to-output dependence based on a Boucherot bridge model of a transformer. Analytical modeling predictions are supported by finite-element analysis results to provide the proof of conceptual finding of this technology. Design procedures for each of the four configurations are presented in detail. A comparison study that highlights the merits and demerits of each configuration is given to help determine the appropriateness of each transformer configuration to a particular application.