Determination of limits on air gap and efficiency for wireless power transfer via magnetic resonant coupling by using equivalent circuit

Abstract

Recently, there has been considerable progress in wireless power transfer technology. The use of magnetic resonant coupling has resulted in a large air gap and high efficiency. So far, this technology has been studied by considering an equivalent circuit. However, the limits on the air gap and efficiency are not specified by the equivalent circuit. This paper proposes equations that specify the limits on the air gap and efficiency for wireless power transfer via magnetic resonant coupling. Moreover, circuit conditions that are required to achieve a large air gap and high efficiency are proposed. © 2010 The Institute of Electrical Engineers of Japan.