Capacitive Wireless Power Transfer with Multiple Transmitters: Efficiency Optimization

Abstract

<jats:p>Wireless power transfer with multiple transmitters can have several advantages, including more robustness against misalignment and extending the mobility and range of the receiver(s). In this work, the efficiency maximization problem is analytically solved for a capacitive wireless power transfer system with multiple coupled transmitters and a single receiver. It is found that the system efficiency can be increased by adding more transmitters. Moreover, it is proven that the cross-coupling between the transmitters can be eliminated by adding shunt susceptances at the input ports. Optimal values for the input currents and receiver load are determined to achieve maximum efficiency. As well the optimal load, the optimal input currents and the maximum efficiency are independent on the cross-coupling. By impedance-matching the internal conductances of the generators, the maximum-efficiency solution also becomes the one that provides the maximum output power. Finally, by expressing each transmitter–receiver link with its kQ-product, the maximum system efficiency can be calculated. The analytical results are verified by circuital simulation.</jats:p>

A Comprehensive Review on Wireless Capacitive Power Transfer Technology: Fundamentals and Applications

“…Multiple transmitters/receivers applications can be categorized as multiple transmitters with a single receiver, multiple receivers with a single transmitter, and multiple transmitters and multiple receivers in CPT systems. The CPT with multiple transmitters is proposed to improve the system efficiency [301]. According to that, the system efficiency can be enhanced by adding more transmitters.…”

“…• Increased power density [62,296] • Increased power transfer capacity [288,293,296] • High efficiency [288,294] • Reduced voltage and current stress [289] • Power transfer ability across the metal object [290] • High tolerance to misalignments [294,295] • Mix switching ability [298] • Relatively low efficiency [62,289] • High occupied space [288,294,295] • Design complexity [290,293,296,298] • Increased cost [294,296] Multiple transmitters/ receivers • Reduced charging time for receivers [171,302,[304][305][306][307] • Charging multiple receivers at once [171,302,[304][305][306][307] • Power maximization [304,309] • Efficiency maximization [301,302] • High tolerance to parameter variations [171,305,307] • High tolerance to misalignments [301,306] • High mobility and range ability…”

A Novel Compensation Circuit for Capacitive Power Transfer System to Realize Desired Constant Current and Constant Voltage Output

“…Compared to the traditional plug-in charger, the wireless power transfer (WPT) technique possesses the advantages of convenience, safety, and isolation [1,2]. The inductive power transfer (IPT) technique [3][4][5] and capacitive power transfer (CPT) technique [6][7][8] are two main solutions of WPT. The coupler of IPT is two physically separated coils of a loosely coupled transformer.…”

8-Plate Multi-Resonant Coupling Using a Class-E2 Power Converter for Misalignments in Capacitive Wireless Power Transfer

“…IPT is widely applicable in the present market for its high-power transfer capability with a greater than 90% efficiency [6]. However, in recent years, capacitive-wireless power transfer (CPT) has gained attention because of its compact, cost-efficient, and flexible coupling nature [7]. Compared with IPT, CPT utilizes high frequency (MHz) electric fields to deliver power from the transmitter to the receiver [8].…”