无线手机充电器控制电路外文翻译资料

武汉理工大学毕业设计（论文） 外文翻译

毕业设计（论文）题目：无线手机充电器控制电路

2020 年 3 月 1 日

目录

1. Wireless Charging of a Metal-Body Device....................................................................................................................1

II. RESONATOR DESIGN 1

III. EQUIVALENT CIRCUIT 4

IV. FABRICATION 5

V. MEASUREMENT 7

VI. CONCLUSION 9

REFERENCES 9

用于金属体设备的无线充电器 11

2.谐振器设计方案 12

3.等效电路 15

4.制作过程........................................................................................................................................................................19

5.计算................................................................................................................................................................................21

6.结论 26

参考文献...........................................................................................................................................................................27

Wireless Charging of a Metal-Body Device

Nathan Seongheon Jeong, Member, IEEE, and Francesco Carobolante, Member, IEEE

Abstract— Conventional tightly coupled inductive charging has been popular in the mobile device market for years. However, tightly coupled solutions have been unable to efficiently charge a metal encased device due to substantial heat generation. In this paper, we demonstrate that loosely coupled inductive charging technology is a viable solution to charge a metal encased device. Ample power can be delivered through the metal case with negligible case heating. Our prototype is built by machining a lump of aluminum which is attached to a commercial smart phone. Resonator coupling efficiency is measured to be 90% with a certified AirFuel Alliance transmitter. Measured power to a load is 8.2 W, which is suitable for mobile devices.

Index Terms— Airfuel alliance (AFA), loosely coupled resonant system, magnetic resonance, metal body wireless charging.

1. INTRODUCTION

W

IRELESSLY charging electronic devices are widely available today but their charging capability has been

greatly limited by the inability to charge a metal-body device. In mobile device charging, tightly coupled inductive charging technology has been extensively adopted in recent years [1]–[7]. Typically, its operating frequency is in the range of 100 to 200 kHz, as developed and promoted by the wireless power consortium. Such technology necessitates strong mutual coupling between a power transmitting unit (PTU) and a power receiving unit (PRU) leading to a high coupling coefficient up to 0.9. Because of this stringent requirement, it further requires a PRU to be precisely aligned with a PTU. Although resonant coupling can be implemented also at these lower frequencies, thus obviating the need for precise alignment, one critical drawback is that a metal body electronic device cannot be charged due to substantial heat generation by induced eddy current [2].

Loosely coupled magnetic resonant charging technology provides significant advantages relative to tightly coupled inductive charging technology [8]–[13], also thanks to utilizing a higher frequency. As specified by AirFuel Alliance (AFA), formerly the Alliance for Wireless Power (A4WP), it operates at 6.78 MHz and leverages resonance to enable coupling coefficients that can be less than 0.1, permitting spatial freedom in any directions or orientations. This feature allows users to freely place their mobile devices within a charging area or volume. Furthermore, eddy currents are substantially

Manuscript received July 23, 2016; revised January 18, 2017; accepted February 5, 2017. This work was supported in part by the Qualcomm WiPower team. This paper was presented at the IEEE MTT-S Wireless Power Transfer Conference, Aveiro, Portugal, May 5–6, 2016.

The authors are with Qualcomm Technologies Inc., San Diego, CA 92121 USA (e-mail: seongheo@qti.qualcomm.com; fcarobol@qti. qualcomm.com).

Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org.

Digital Object Identifier 10.1109/TMTT.2017.2673820

Fig. 1. Metal body device above a magnetic field emanating transmitter.

lower due to the higher frequency, facilitating charging through a metal body. Another advantage of magnetic resonance technology is its ability to charge multiple devices simultaneously with a single transmitter. Low and high power can be concurrently delivered to substantially different devices, from wearables to smartphones and notebooks. Fig. 1 shows an example of a loosely coupled charging system where a PTU defines an available wireless charging volume and a PRU is placed anywhere within the volume. The magnetic linkage is made through a vertically polarized magnetic field. Since the development of this technology, a major challenge has been to charge a device with a metal body, which is common for many devices in the market, from smartphones to tablets. In 2015 for the first time, we demonstrated the feasibility of wireless charging a metal encased smartphone at the Mobile World Congress in Spain. The work has been recently published in a short paper [14]. In this paper, we further investigate the design to provide details of theoretical analysis, desig

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