Constant output characteristics and design methodology of double side LC compensated capacitive power transfer

Qiao Xiong,Jun Sun,Enguo Rong,Pan Sun,Yan Liang,Ying Shao

doi:10.1038/s41598-022-06577-x

Abstract

Capacitive power transfer (CPT) has been verified to be capable of transferring a power level as high as inductive power transfer (IPT) recently, and has its own merits. It is a well complement of IPT in near-field wireless power transfer (WPT). This paper gives a newly designed method of realizing both constant output voltage (COV) and constant output current (COC) modes of double side LC compensated CPT. Firstly, through analysis of basic circuit characteristics, the conditions for both of the two modes are deduced theoretically. Especially, one merit of the method is that the conditions indicate a very clear relationship between the compensation components forming resonant tanks. Another merit is that the couple capacitors also participate in resonant tanks. Different from the COV mode, the COC mode can theoretically reach zero phase angle condition simultaneously. Based on these conditions, the parameter design methodology is proposed. Besides, an efficient model of double side LC compensated CPT is built, and the optimum load is calculated theoretically to guide the design course. Finally, the results of both simulations and experiments demonstrate high consistency with the theoretical analysis.

Highlights

Capacitive power transfer (CPT) has been verified to be capable of transferring a power level as high as inductive power transfer (IPT) recently, and has its own merits
In the past few years, inductive power transfer (IPT) utilizing inductive coils is most widely studied as a conventional wireless power transfer (WPT) technology, though some technical obstacles are difficult to overcome, like bulky couple structure, eddy current loss in nearby conductive objectives, weak performance when m isaligned[1,2]
CPT with double side LC compensation net is a nalyzed[18,19,21,25,30], especially both constant output voltage (COV) and constant output current (COC) conditions are proposed based on the deduction of voltage or current g ain[19]

Summary

Introduction

Capacitive power transfer (CPT) has been verified to be capable of transferring a power level as high as inductive power transfer (IPT) recently, and has its own merits. CPT with double side LC compensation net is a nalyzed[18,19,21,25,30], especially both constant output voltage (COV) and constant output current (COC) conditions are proposed based on the deduction of voltage or current g ain[19]. Conditions for both the COV mode and COC mode attribute to operation frequencies different from the intrinsic resonant frequency of the LC compensation net in either the primary side or secondary side, leading to a vague relationship between the resonant components. The couple efficiency in an ordinary CPT system is generally very low, leading to a very vicinal operation frequencies for COV and COC modes, which would be in high accordance with the intrinsic resonant frequency of the LC compensation net.

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Conclusion