Ferrite core couplers for inductive chargers

Growing attention is being directed to inductive charging as a battery charging method for electric vehicles, due to its safe operation even under wet and stained conditions. For inductive charging, paddle and disc structures have been proposed. The paddle type can be a compact structure, but its rapid (large power) charging capacity is limited. Although the disc type can handle a large power, it is disadvantaged by its heavy weight and difficult position matching between the feeder and receiver discs. Since light weight and large power transmission are two essential prerequisites for automotive use, it will be the best to combine the advantages of the paddle and disc type inductive chargers. In this paper, we report our experiment on reducing the weight and facilitating the position matching of ferrite core discs for inductive chargers, using non-contact disc couplers. Our two important findings: First, the disc weight can be reduced to three-eighths by dividing each disc and removing some of the disc slices, while a sufficient amount of power transmission is maintained. Second, by pairing the upper and lower disc slices in partial overlap, a satisfactory coupling efficiency is achieved even if the horizontal lag between the two discs is widened 1.7 times.