Moving pick-up type contactless power transfer systems and their efficiency using series and parallel resonant capacitors

The equivalent circuit, the efficiency and the important characteristics of moving pick-up type contactless power transfer systems are described. If primary series capacitor and the secondary parallel capacitors are chosen correctly and the winding resistances are ignored, the equivalent circuit of the transformer with these capacitors becomes the same as an ideal transformer at the resonant frequency. This simple approximation helps to understand the phenomena with load changes. As the circuit analysis becomes simple, the approximate value of power transfer efficiency can be derived. This paper describes the determination of the capacitor values, the derivation of the equivalent circuit and the efficiency and the test results. © 2008 The Institute of Electrical Engineers of Japan.