Frequency splitting patterns in wireless power relay transfer

Abstract

Frequency splitting patterns in low-order wireless power relay transfer systems are analysed by the coupled-mode theory. In addition to the V-type splitting pattern reported widely, two new patterns, I-type and W-type, are introduced. Specifically, it is found that a 0-relay system shows a V-type or I-type splitting; a symmetrical 1-relay system shows an I-type or W-type splitting; and a symmetrical 2-relay system usually shows a V-type or W-type splitting. The criteria for different frequency splitting patterns are given, and the theoretical results are validated finally by 1-relay and 2-relay wireless power transfer experimental systems.

Frequency Splitting Elimination and Cross-Coupling Rejection of Wireless Power Transfer to Multiple Dynamic Receivers

“…In case of multiple Rx system which is operated at different resonant frequency employing the impedance matching circuit increases the design complexity and requires a wide range of capacitance and inductive elements. Therefore, to minimize the effects of frequency splitting with simple control approach a non-identical resonant coil structure was studied for different distance in single Tx and Rx system [30,31]. However, in case of lower power multiple, Rx WPT system the size of the Rx coils is restricted which requires the optimal design of non-identical Tx and Rx coil by considering the Rx coil size constraints.…”

Analysis and experimental results of frequency splitting of underwater wireless power transfer

“…Frequency splitting is a critical issue related to wireless power transfer (WPT) systems transfer performance in air. Frequency splitting is a phenomenon of WPT systems when the coupling between the Tx and Rx coils becomes larger gradually and greater than the critical coupling, the frequency characteristics of load power change from a single peak to a multi‐peak [5–10]. A V‐type splitting pattern of a two‐coil WPT system is reported and analysed widely in the publications [7–9].…”

“…Frequency splitting is a phenomenon of WPT systems when the coupling between the Tx and Rx coils becomes larger gradually and greater than the critical coupling, the frequency characteristics of load power change from a single peak to a multi‐peak [5–10]. A V‐type splitting pattern of a two‐coil WPT system is reported and analysed widely in the publications [7–9]. At the fixed operation frequency, tighter coupling leads to higher power transfer in undercoupled region [11], while tighter coupling results in lower power transfer in overcoupled region by frequency splitting [7–9].…”

Voltage transfer ratio analysis for multi‐receiver resonant power transfer systems

“…In an advanced WPT system, a large single source can be used to transfer power to multiple small devices [11][12][13]. Multi-receiver coil systems present better overall transfer efficiency than single-receiver systems, while the efficiency becomes low when devices are added [12,14,15]. The upper bound of the power transfer efficiency under multiple transmitters can be found using a numerical search [16].…”