A ring inductive power transfer system

Abstract

Inductive Power Transfer (IPT) is an efficient and well established technique for contactless or wireless power transfer, and has numerous applications over a wide power range. Although the demand for high power IPT systems is growing, the implementation of such IPT systems is severely hampered by the limitations of voltage and current ratings of available semiconductor devices. This paper presents a new ring IPT system, which employs semiconductor devices in the current market and is still capable of generating high track currents, without which the design of high power IPT systems becomes practically impossible. The proposed ring IPT system facilitates easy integration of multiple IPT power supplies, which are made of general and freely available semiconductor components, to generate a high track current. An independent ring type track, comprising an inductor-capacitor-inductor (LCL) network, serves as an intermediate circuit through which the power transfer between primary supplies and pickup systems takes place. The ring circuit is magnetically coupled to multiple primary supplies and pickup systems, and combines primary supplies in series to generate a high track current. The power flow of the system is controlled by phase and/or magnitude modulation of voltages generated by both primary power supplies and pickup systems. Theoretical analysis is presented with simulations to show that the proposed ring IPT system is ideal for generating high track currents required for high power applications, and is flexible for both bi-directional and unidirectional contactless power transfer.