Capacitive power transfer through virtual self‐capacitance route

Abstract

This study presents the modelling, analysis, and experimental results of a novel capacitive power transfer (CPT) structure with a single coupling capacitor. It is noticed that each charged object has a nature property called self-capacitance, which is a kind of capacitance with respect to infinity. Taking advantage of this property, the conventional CPT structure can be simplified. Instead of using two capacitors to form the closed coupling loop, one of them is replaced by two metallic blocks with relatively big self-capacitances. Even though there is no physical coupling between the two blocks, they can be considered as virtually connected through their self-capacitances to infinity, which forms the return route for the proposed CPT structure. To achieve precise analysis, the detailed circuit model is established with the consideration of self-capacitances for both the blocks and coupling plates. Moreover, the results of the applications with attached blocks replaced by robust reference grounds (RRG) are also analysed in order to extend the proposed structure to more scenarios. System performances with and without RRG are compared. Experiments with different capacitor plate sizes at various transfer distances are also conducted. Both the theoretical analysis and experimental results indicate the effectiveness of the proposed structure.

Research and Application of Capacitive Power Transfer System: A Review

“…Reference [15] established a model of a single-capacitor system CPT system and revealed its power transmission property of strong coupling to the ground. Reference [82] proposed a new mid-range air-gap singlecapacitor CPT system in which two metal blocks were used to form a virtual capacitor return route. Therefore, the traditional four-plate structure was simplified to a two-plate structure.…”

Characterization of a resonant capacitively coupled wireless power transfer system for communication purposes at 6 MHz

“…Thus, in order to transmit power and data efficiently, the complex consisting of the Tx‐resonator, Rx‐resonator, and the capacitor between them must be designed to resonate collectively, with zero current boundaries at the open ends. The self‐capacitance between the Tx‐ and Rx‐ resonators closes the circuit loop [17].…”

Analysis, design and evaluation of a zero‐voltage‐switching non‐resonant converter for IPT applications

“…The peak value of current i 2 can be calculated as I 2m = 2V o /R, where R is the load resistance. Now, current i 2 can be expressed as in (5) and 6as…”

“…Among the most common WPT methods the following stand out: inductive power transfer (IPT), capacitive power transfer, radiofrequency power transfer, light power transfer and acoustic power transfer [2][3][4][5][6][7]. At the present time, the IPT method, based on magnetic fields, is the one that provides the highest efficiency (80-95%), highest output power range (up to 200 kW) and high frequency operating range (20 kHz-20 MHz).…”