Dual-Band Free-Positioning Transmitting Coil for Multiple-Receiver Wireless Power Transfer

Hoang Le-Huu,Chulhun Seo

doi:10.1109/access.2021.3101635

Hoang Le-Huu, Chulhun Seo

Open Access

https://doi.org/10.1109/access.2021.3101635

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Abstract

In recent years, the requirement for a compact wireless power transfer (WPT) system that can supply power to multiple devices in various practical usage scenarios has been attracted many researchers. The receiver (Rx) misalignment problem is contributory to the power transfer efficiency (PTE) degradation. Moreover, in a multiple-output WPT system, the overall system efficiency is also affected by cross-coupling between receivers. This paper proposes a dual-band free-positioning transmitting coil (FPDB-Tx) for multiple-receiver WPT. A three-dimensional Tx structure is modeled by investigating the current direction on each coil loop to adapt the Rx angular and axial misalignment. The Tx configuration is designed following a wireless charging box concept, where multiple Rx devices can receive energy freely without a null efficiency point. The mutual inductance is examined by a mathematical method in various Rx orientations to verify the free-positioning characteristic. Furthermore, an equivalent circuit model of the WPT system is theoretically analyzed to obtain dual operating frequency bands and then maximized the PTE. The experimental results show that the proposed WPT system achieves a stable PTE in various Rx positions. Especially, the WPT system has a maximum PTE of 97.27% and 91% at 6.78 MHz and 13.56MHz, respectively.

Highlights

W IRELESS power transfer (WPT) is a promising solution to safely supply power to consumer device in various applications [1]–[4]
In a practical magnetic resonant coupling (MRC)-wireless power transfer (WPT) system, the changes in positions of receiver (Rx) devices cause the variation on mutual coupling because the magnetic field of a typical transmitter (Tx) coil is not uniformly distributed [6]–[15]
DUAL-BAND FREE-POSITIONING WIRELESS POWER TRANSFER TO MULTIPLE RECEIVERS A typical planar Rx coil can receive the most power from the Tx coil when the generated field vectors are perpendicular to the Rx plane

Summary

INTRODUCTION

W IRELESS power transfer (WPT) is a promising solution to safely supply power to consumer device in various applications [1]–[4]. A dual-band free-positioning transmitter (FPDB- Tx) coil, which can transfer power effectively to multiple Rx devices in various coil arrangements, has been proposed. DUAL-BAND FREE-POSITIONING WIRELESS POWER TRANSFER TO MULTIPLE RECEIVERS A typical planar Rx coil can receive the most power from the Tx coil when the generated field vectors are perpendicular to the Rx plane. The mutual inductance is evaluated based on the coil configurations and coil arrangements.To obtain a freepositioning WPT system with high performance, the field intensity should be strong and distributed in multiple directions to adapt to the Rx lateral displacement and angular misalignment. A. FREE-POSITIONING TRANSMITTING COIL USING DOUBLE REVERSED COIL LOOP Fig. 1 illustrates the proposed FPDB-Tx configuration in two verification scenarios of a single receiver and multiple receivers. By substituting (14) to (13), the dual-band operating frequencies can be determined by:

MULTIPLE-RECEIVER WPT SYSTEM

DUAL-BAND MULTIPLE-RECEIVER WPT SYSTEM

Findings

CONCLUSION