Magnetic resonance wireless power transfer using three-coil system with single planar receiver for laptop applications

Abstract

This paper presents a magnetic resonance wireless power transfer (WPT) system that uses three coils, a planar receiver and operates at 6.78 MHz,. Effective power transfer is ensured by establishing an impedance matching condition for this WPT system. A metamaterial (MTM) array having dimensions of 20 cm. 30 cm is also positioned near the load coil to concentrate the magnetic field and enhance the transfer efficiency. The result is a maximal improvement of 27% in the transfer efficiency at a transfer distance of 50 cm. The impact of a ground plane on the transfer efficiency is also examined. By utilizing the MTM array, making slits on the ground plane and increasing the gap between the ground plane and the load coil, it is possible to mitigate this impact. The highest transfer efficiency improvement is about 55% at a distance of 20 cm with the ground plane. A practical laptop model is fabricated to verify the impact of the load coil angle and position on the transfer efficiency. The result shows that the maximum transfer efficiency with the laptop model is 47.58% with the load coil angle of 90 degree(1)

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

“…Quality factor of the coil reduces due to the increase in the source and load port resistance of the circuit, which can be minimized by adding a relay coil to the circuit. The three coil WPT circuit gives a better power delivered to the load and PTE as compared with the four coil WPT circuit [34].…”

“…The equivalent circuit of three coil MRWPT system is shown in Figure 2, consist of Tx coil, Rx coil and load coil. WPT circuit gives a better power delivered to the load and PTE as compared with the four coil WPT circuit [34]. However, for the selective power distribution using time division multiplexing requires to tune the Tx coil frequency which makes difficult to add a relay coil at the transmitter section.…”

An improved three-coil wireless power link to increase spacing distance and power for magnetic resonant coupling system

“…[0.5j(ω 1 − ω 2 )t], where A(t) is a slowly varying time domain function. Assume there is an initial condition as Γ{t = 0, a 1 (t) = A(t); a 1 (t) = 0}, the solution can be derived as (2), where ω is the average value of ω 1 and ω 2 .…”

“…The magnetic resonant coupling wireless power transfer (MRC-WPT) was first proposed by MIT's team in 2007 [1] and is now gaining more spotlights ranging from contactless battery charging of consumer electronics [2], electric vehicles [3][4][5], to biological implanted devices' power supply [6,7].…”

Design Optimization Method for the Load Impedance to Maximize the Output Power in Dual Transmitting Resonator Wireless Power Transfer System

“…In literature, there have been proposed a number of applications of resonant inductive coupling WPT to various apparatus, such as laptops (10) , biomedical implants (11)- (14) , and electric vehicles (15)- (19) . Particularly, application of WPT to small mobile apparatus, such as mobile phones and laptops, is emerging as a promising field of techniques.…”