Investigation of magnetic resonance coupling circuit topologies for wireless power transmission

Abstract

Magnetic resonance coupling circuits have four general topologies; however, there is a lack of comprehensive theoretical analysis with experimental verification for each of these topologies regarding their attractiveness for wireless power transfer (WPT). This article provides this for each of the four topologies to fully understand their differences and allow the selection of the most appropriate type based on system requirements. In addition, a problem associated with the resonance coupling method is the phenomenon of frequency splitting, which can lead to a high‐power transfer efficiency but low‐load power at the resonant frequency. Reasons for frequency splitting and methods of circumventing the problem will be illustrated in this article. Of the four topologies, the series‐parallel (SP) (input‐output) circuit configuration is the most efficient for the realization of a WPT system with a large load impedance, in terms of achieving both a high power transfer efficiency and high‐load power.

A new coil structure for positioning estimate of wireless power transmission

“…Based on Kirchhoff's law and related circuit theory, the system relationship matrix can be obtained as shown in formula (14).…”

“…However, there were only a few attempts to determine the optimal location for wireless charging. 14 Different from the previous literature, this article proposes a breakthrough idea, which is to use mutual inductance to achieve accurate positioning of wireless charging. In order to develop a method of precise positioning, a coil structure for wireless charging has been skillfully designed in this article.…”

“…In the existing literature, the methods for maximizing transmission efficiency had been reviewed, and a lot of research had been done on wireless charge resistance. However, there were only a few attempts to determine the optimal location for wireless charging 14 …”

Interference Analysis of Metal Conductors for Target-Resonance-Based Detection Method

“…When the coupling coefficient between the transmitting coil and the receiving coil is too large in the MCR-WPT system, the power transfer will be influenced significantly [7]. In the output side, frequency splitting phenomenon occurs, where the load power-frequency curve changes from a single-peak curve to a double-peak curve, and meanwhile the output power of the energy transfer system cannot reach the maximum [8]. Numerous literatures focus on the causes of frequency splitting [9], the derivation of frequency splitting equations [10], the system structure optimization [11][12][13], frequency tracking [14], etc., and devote to eliminating frequency splitting or achieving optimal energy transfer in the case of frequency splitting.…”

A Conformal Split-Ring Loop as a Self-Resonator for Wireless Power Transfer

“…The equivalent circuit of a conventional PSC is a parallel LC network hence using a pair to form a WPT system would constitute a parallel-primary and parallelsecondary system. However, the parallel-parallel topology offers poor power transfer performance, since the voltage source would be loaded by an open circuit at resonance if directly connected [18]. The series-primary, series-secondary topology and the series-primary, parallel-secondary topology are most typically used for wireless power transfer.…”