Coupling-Independent Capacitive Wireless Power Transfer Using Frequency Bifurcation

Ben Minnaert,Nobby Stevens,Mauro Mongiardo,Franco Mastri,Alessandra Costanzo

doi:10.3390/en11071912

Abstract

Capacitive wireless power transfer can be realized by mutually coupled capacitors operating at a common resonant frequency. An optimal load exists that maximizes either the efficiency or the power transfer to the load. In this work, we utilize the frequency bifurcation effect to propose a frequency agile mode that allows for a nearly coupling-independent regime. We analytically determine the operating conditions of the coupling-independent mode based on the different system gains. In this way, we obtain a solution that achieves nearly constant efficiency and power transfer, even at varying coupling. We compare our results to inductive wireless power transfer where a perfect coupling-independent mode is achievable.

Highlights

Wireless power transfer (WPT) allows energy transfer from a transmitter to a receiver across an air gap, without any electrical connections [1,2]
WPT is especially important for biomedical implants such as pacemakers [5], neurostimulators [6] and spinal cord stimulators [7]
We study the fundamental design for achieving a capacitive wireless power transfer (CPT) link that is independent of the coupling between transmitter and receiver by using a frequency agile approach

Summary

Introduction

Wireless power transfer (WPT) allows energy transfer from a transmitter to a receiver across an air gap, without any electrical connections [1,2]. Any device that needs power can become an application for WPT. The current list of applications where WPT is applied, is very diverse [3,4]. Most known WPT applications are portable electronics and household devices (e.g., smartphones, electric toothbrushes, wearables, smart watches). WPT is especially important for biomedical implants such as pacemakers [5], neurostimulators [6] and spinal cord stimulators [7]

Methods

Discussion

Conclusion