Free-Positioning Wireless Power Transfer Using a 3D Transmitting Coil for Portable Devices

Abstract

The free-positioning wireless power transfer (WPT) system has drawn attention in recent years. Traditionally, a WPT system can transfer energy in one or two directions on the same plane, but it leads the restrictions of angle and axis misalignment between a transmitter and a receiver coil. In this paper, we propose a free-positioning WPT system using a three-dimensional cubic-shaped transmitting coil for portable device charging. A small receiving coil is placed inside the transmitter to achieve the transferred energy through the magnetic resonant coupling. In addition, the equivalent circuit and the mutual inductance between the Tx and Rx coils are analyzed. Finally, a practical experiment is implemented to verify the transfer performance, which can reach up to about 50% power transfer efficiency. The proposed system can charge in spatial freedom.

Limiting magnetic exposures using ferrite core and shielding in wireless charging of mobile phones

“…The transmitter and receiver coils were designed by using Equations ( 10) and (11) with the parameters given in Figure 2.…”

“…9 WPT systems have become advantageous in many application areas compared with wired energy transmission systems as they facilitate mobility, provide freedom of movement, and are more safe. Today, this technology is constantly developing in many application areas such as electric vehicles, 10 mobile devices, 11 biomedical implant devices, 12 robotic appliances, 13 and unmanned aerial vehicles. 14 In recent years, a wide variety of studies have been conducted on charging of mobile phones and devices.…”

“…However, due to the losses, only 50%-60% efficiency was achieved in power transmission. 11,13 Due to the fact that the mobile device is in motion during three-dimensional charging, the problem of low efficiency and distance in energy transfer has been examined. 15 In another study, the use of WPT systems in subway trains was examined.…”

A Comprehensive Review of Midrange Wireless Power Transfer Using Dielectric Resonators

“…For the coil structure, several designs ranging from flat printed structured coil (PSC) [15][16][17] to helix [18][19][20][21], square [22][23][24], and 3D [25,26] designs have been implemented. Designs ranging from as simple as a circular structure to other complicated designs have been adopted although the efficiency remained below the targeted value.…”

Compensation for Lateral Misalignment in Litz Wire Based on Multilayer Coil Technology

“…However, it requires relatively large coils, which may not be compatible at kHz frequencies. Otherwise, they have complex structures, are impractical [ 7 , 8 , 9 , 10 , 11 ], or the maximum degree of misalignment to compensate for the decreased efficiency is limited [ 12 ].…”