Design for Efficiency Optimization and Voltage Controllability of Series–Series Compensated Inductive Power Transfer Systems

TLDR

Inductive power transfer is an emerging wireless charging technology, but its complex control and low efficiency, along with conflicting demands for high efficiency and voltage controllability under varying loads, hinder widespread deployment. This study investigates how compensation parameters, circuit efficiency, voltage transfer function, and the conduction angle of the input current relative to the input voltage interrelate. The authors propose a design and optimization method, illustrated with design curves, that balances efficiency gains and switch current ratings to achieve a desired voltage transfer ratio. Experimental results confirm the effectiveness of the proposed approach.

Abstract

Inductive power transfer (IPT) is an emerging technology that may create new possibilities for wireless power charging and transfer applications. However, the rather complex control method and low efficiency remain the key obstructing factors for general deployment. In a regularly compensated IPT circuit, high efficiency and controllability of the voltage transfer function are always conflicting requirements under varying load conditions. In this paper, the relationships among compensation parameters, circuit efficiency, voltage transfer function, and conduction angle of the input current relative to the input voltage are studied. A design and optimization method is proposed to achieve a better overall efficiency as well as good output voltage controllability. An IPT system design procedure is illustrated with design curves to achieve a desirable voltage transfer ratio, optimizing between efficiency enhancement and current rating of the switches. The analysis is supported with experimental results.