Capacitive wireless power transfer by means of adaptive matching networks

Abstract

A controlled wireless Capacitive Power Transfer (CPT) system, based on adaptive matching networks, comprising a primary power transmitter side for wirelessly transmitting power to a secondary power receiver side via coupling plates having mutual capacitance C<M>; a power source connected to a power driver operating a determined switching frequency f<sw>; a primary adaptive matching network for regulating the current flowing to the secondary side via the mutual capacitance C<M>; a primary controller consisting of a first control loop, for adjusting the switching frequency f<sw> to compensate for changes in the impedance of the primary matching network; a second control loop, for adjusting the resonant frequency of the primary resonant circuit to track the switching frequency f<sw> by providing appropriate bias to the primary inductor and changing the resonant frequency of the primary resonant circuit; a secondary adaptive matching network connecting between the mutual capacitance C<M> and the rectifier circuit and consisting of a secondary resonant circuit with a bias-controlled variable secondary inductor serially connected to the mutual capacitance C<M and a parallel capacitor parallely connected to the mutual capacitance C<M , for matching the impedance of the secondary matching network; and a secondary controller for adjusting the impedance of the secondary matching networkto match the resonant frequency of the primary resonant circuit by providing appropriate bias to the secondary inductor.

Description

technical field [0001] The present invention generally relates to the field of wireless power transfer (WPT). More specifically, the present invention relates to a system for efficiently and wirelessly performing capacitive power transfer (CPT) using an adaptive matching network. Background technique [0002] Today, there is an increasing demand for mobile power, which is necessary to keep high-performance devices available for long periods of time, even continuously. Wireless Power Transfer (WPT) technology potentially provides energy at all times and reduces the reliance on bulky batteries as a reliable primary energy source for weight- and volume-sensitive mobile and portable applications. [0003] One of the solutions for WPT is the capacitive power transfer (CPT) method. CPT is an alternative near-field power transfer method to the well-known magnetic field-based methods. One of the more attractive advantages of capacitive-based WPTs is the avoidance of undesirable e...

AI Technical Summary

Problems solved by technology

The latter provides flexibility for regulating the power delivered to the load, but requires additional control circuitry and a potential deterioration in overall efficiency

Although existing closed-loop methods are able to overcome some system variations and can extend the power delivery range, a single control method is not enough to guarantee the reliable operation of WPT systems

[0007] Magnetic field-based WPT methods and particularly magnetic resonance, combined control methods have been proposed, however, closed-form control mechanisms for CPT have not yet been addressed

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