A Dual-Side-Detuned Series–Series Compensated Resonant Converter for Wide Charging Region in a Wireless Power Transfer System

Wireless power transfer (WPT) system usually suffers from wide range of coupling condition. This causes deep impact on the transferred power level, which further limits the mobility of receiver. In this paper, a dual-side-detuned series-series (SS) compensation method is proposed to provide stable power transfer over wide geometric area. The primary and secondary tuning methods are classified into three categories, respectively, namely fully tuned, inductively tuned, and capacitively tuned. Then, the general power transfer characteristic against coupling factor is identified and it is found that the primary inductively and secondary capacitively tuned (PISC) system is advantageous over other candidates in performance, especially the resistance to variation of coupling factor. Compared to conventional fully tuned SS system, the PISC-type WPT system provides much wider stable power transfer region, which enables higher mobility for the receiver side. The design consideration and principle of the detuned resonant tank is developed, based on which the iteration approach is proposed to guide parameter design procedure. Finally, the validity of the proposed dual-side-detuned SS topology is experimentally verified. Under coupling variation from 0.08 to 0.2, the power transfer is maintained above 80% of its nominal power level with agreeable efficiency.