Analysis and Design of Asymmetric Mid-Range Wireless Power Transfer System with Metamaterials

Abstract

In a wireless power transfer (WPT) system, the power transfer efficiency (PTE) decreases sharply with the increase in transfer distance. Metamaterials (MMs) have shown great potential to enhance PTE in mid-range WPT systems. In this paper, we propose two MM slabs of a 3 × 3 array to enhance the magnetic coupling. The MM unit cell was designed by using square spiral patterns on a thin printed circuit board (PCB). Moreover, the asymmetric four-coil WPT system was designed and built based on the practical application scenario of wireless charging for unmanned devices. The simulation and experimental results show that two MM slabs can enhance power transmission capability better than one MM slab. By optimizing the position and spacing of two MM slabs, the PTE was significantly improved at a mid-range distance. The measured PTEs of a system with two MM slabs can reach 72.05%, 64.33% and 49.63% at transfer distances of 80, 100 and 120 cm. When the transfer distance is 100 cm, the PTE of a system with MMs is 33.83% higher than that without MMs. Furthermore, the receiving and load coils were integrated, and the effect of coil offset on PTE was studied.

High-Efficiency Wireless-Power-Transfer System Using Fully Rollable Tx/Rx Coils and Metasurface Screen

“…However, a concern is that some previously reported MTMs have had bulky and volumetric structures such as 3D and thick. printed circuit-board-based structures, reducing the practicality of MTM slabs [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. If additional volumetric MTM slabs were permanently located in the power-transfer path, it would greatly limit the usage of the space, diminishing the usefulness of the WPT system.…”

“…Specifically, for the efficient utilization of space, modern commercial electronic devices change their form factors and are deformed, folded, and rolled, e.g., foldable, flipped phones, and rollable televisions, without degrading the performance of the electronic devices while promoting their portability. In this respect, previously demonstrated WPT systems utilizing MTMs have not been compliant with this trend, as their structures have been thick, huge, or rigid [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ] for modern electronic devices. In our previous work [ 14 ], a rollable MTM screen for a high-efficiency WPT system was designed at 4.5 MHz, where only the MTM screen was rollable, while the source, Tx, Rx, and load coils were made of non-planar and non-rollable rigid structures.…”

Design of new metamaterial with negative permeability for efficient wireless power transfer

“…Aside from one MTM slab, it is revealed that two MTM slabs are more advantageous for efficient power transfer. In Zeng et al, 31 a midrange distance WPT system with two MTM slabs of a 3 × 3 array is proposed to enhance magnetic coupling between coils. The study shows that the power transfer efficiency of the proposed system is higher than that of WPT with one MTM slab.…”

The Efficiency Improvement of Multiple Receivers in Wireless Power Transmission by Integrating Metasurfaces

“…Metamaterials or metasurfaces are widely used to improve the WPT efficiency of their unique electromagnetic properties [ 14 , 15 , 16 ], which is not seen in natural materials, such as the zero refraction metamaterials, the negative refractive index (NRI) and negative permeability (MNG) metamaterials [ 17 , 18 , 19 , 20 , 21 , 22 ]. The authors in [ 14 ] propose two metamaterial slabs of a 3 × 3 array to enhance the magnetic coupling. The influence of electromagnetic metamaterials on the WPT system under the conditions of lateral misalignment and angular offset was investigated in [ 15 ].…”