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.