• Title, Summary, Keyword: wireless power transfer

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Magnetic Field Analysis of Wireless Power Transfer via Magnetic Resonant Coupling or Electric Vehicle

  • Kesamaru, Katsumi
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.1
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    • pp.83-87
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    • 2014
  • This paper describes the magnetic field analysis of wireless power transfer via magnetic resonant coupling. The wireless power transfer system for supplying power to electric vehicle is developed. The parameters of coil transfer system are simulated by the finite element method (FEM). Therefore the coil structure of power transfer system can be accurately analyzed. This paper deals with 3kW wireless transfer system.

Implementation of Inductive Wireless Power Transfer System based on LLC Converter without Wireless Communication between Tx and Rx (Tx-Rx간 무선통신이 필요 없는 LLC 컨버터 기반 유도형 무선전력전송 시스템 구현)

  • Kim, Moon-Young;Choi, Shin-Wook;Kang, Jeong-il;Han, Jonghee
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.5
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    • pp.311-318
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    • 2019
  • In general wireless power transfer systems (WPTSs), power transfer is controlled by the wireless communication between a transmitter (Tx) and a receiver (Rx). However, WPTS is difficult to apply in electronic products that do not have batteries, such as TVs. A WPTS with resonators based on a transformer of LLC series resonant converter is proposed in this study to eliminate wireless communication units between a Tx and an Rx. The proposed system operates at the boundary of the resonance frequency, and the required power can be stably supplied to authorized devices even though some misalignment occurs. Moreover, standby power standards for the electronic product can be satisfied.

Relation between Induced Voltage of Rail and Feeding Line of Wireless Power Transfer System for Railway Application (철도용 무선전력전송시스템의 급전선로와 레일유기전압의 관계)

  • Kim, JaeHee;Park, Chan-Bae;Jung, Shin-Myung;Lee, Seung-Hwan;Lee, Byung-Song;Lee, Jun-Ho;Lee, Su-Gil
    • Journal of the Korean Society for Railway
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    • v.17 no.4
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    • pp.228-232
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    • 2014
  • The magnetic field generated by the feeding line of a wireless power transfer system induces voltage on the rail of a railway system. The induced voltage of the rail can have a bad influence on the track circuit and on safety. This paper simulated three feeding lines to study the relation between the feeding lines and the induced voltage of the rail; it also proposed magnetic field distribution of the feeding line to reduce the induced voltage.

Operation of battery-less and wireless sensor using magnetic resonance based wireless power transfer through concrete

  • Kim, Ji-Min;Han, Minseok;Lim, Hyung Jin;Yang, Suyoung;Sohn, Hoon
    • Smart Structures and Systems
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    • v.17 no.4
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    • pp.631-646
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    • 2016
  • Although the deployment of wireless sensors for structural sensing and monitoring is becoming popular, supplying power to these sensors remains as a daunting task. To address this issue, there have been large volume of ongoing energy harvesting studies that aimed to find a way to scavenge energy from surrounding ambient energy sources such as vibration, light and heat. In this study, a magnetic resonance based wireless power transfer (MR-WPT) system is proposed so that sensors inside a concrete structure can be wirelessly powered by an external power source. MR-WPT system offers need-based active power transfer using an external power source, and allows wireless power transfer through 300-mm thick reinforced concrete with 21.34% and 17.29% transfer efficiency at distances of 450 mm and 500 mm, respectively. Because enough power to operate a typical wireless sensor can be instantaneously transferred using the proposed MR-WPT system, no additional energy storage devices such as rechargeable batteries or supercapacitors are required inside the wireless sensor, extending the expected life-span of the sensor.

Capacitive Coupling LLC Wireless Power Transfer Converter Through Glasses of Electric Vehicles (전기자동차의 유리를 통한 커패시티브 커플링 LLC 무선 전력 전송 컨버터)

  • You, Young-Soo;Yi, Kang-Hyun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.6
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    • pp.542-545
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    • 2016
  • This work proposes a capacitive coupling-based wireless battery charging circuit that is built with vehicle glasses for electric vehicles. A capacitive coupling wireless power transfer offers many advantages, such as low metal impact and low energy transfer efficiency changes in accordance with changes in position. However, a large coupling capacitor is needed for high power transfer. Therefore, a new capacitive coupling-based wireless power transfer LLC resonant converter built with the glasses of an electric vehicle is proposed. The proposed converter is composed of coupling capacitors with glasses of an electric vehicle and two transformers for impedance transformation. The proposed LLC converter can transfer large power and obtain high efficiency with zero voltage switching. The validity and features of the proposed circuit is verified by experimental results with a 1.2 kW prototype.

Analysis of the Efficiency According to Resonant Repeater Application in Magnetic Resonant Wireless Power Transfer System (자기공진방식의 무선전력전송 시스템에서 공진 중계기 적용 여부에 따른 전력전송 효율 분석)

  • Baek, Seung-Myung;Kim, Dong-Eun;Shon, Jin-Geun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.67 no.4
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    • pp.221-226
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    • 2018
  • In this paper, the power transfer efficiency analysis based on the resonant repeater in a magnetic resonance wireless power transfer system is proposed. The efficiency of the magnetic resonance method was verified by comparing the general frequency with the resonance frequency. The resonance repeater was arranged to increase the efficiency and increase the transfer distance. When using resonant repeaters, the maximum efficiency increase is about 36.23[%] and the transfer distance was extended to more than 20[cm]. Through this study, confirmed the effect of using resonance repeaters in wireless power transfer system. As a result, it can be expected that the overall technology related to wireless power transfer system will be more valuable for energy-IT technology.

Enhancement of Wireless Power Transfer Efficiency Using Higher Order Spherical Modes

  • Kim, Yoon Goo;Park, Jongmin;Nam, Sangwook
    • Journal of electromagnetic engineering and science
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    • v.13 no.1
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    • pp.38-43
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    • 2013
  • We derive the Z-parameters for the two coupled antennas used for wireless power transfer under the assumption that the antennas are canonical minimum scattering antennas. Using the Z-parameter and the maximum power transfer efficiency formula, we determine the maximum power transfer efficiency of wireless power transfer systems. The results showed that the maximum power transfer efficiency increases as the mode number or the radiation efficiency increases. To verify the theory, we fabricate and measure two different power transfer systems: one comprises two antennas generating $TM_{01}$ mode; the other comprises two antennas generating $TM_{02}$ mode. When the distance between the centers of the antennas was 30 cm, the maximum power transfer efficiency of the antennas generating the $TM_{02}$ mode increased by 62 % compared to that of the antennas generating the $TM_{01}$ mode.

A Feedback Circuit of Effective Wireless Power Transfer for Low Power System

  • Lho, Young Hwan
    • Journal of IKEEE
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    • v.22 no.2
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    • pp.480-483
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    • 2018
  • Wireless power transfer (WPT) is the technology that forces the power to transmit electromagnetic field to an electrical load through an air gap without interconnecting wires. This technology is widely used for the applications from low power smartphone to high power electric railroad. In this paper, the model of wireless power transfer circuit for the low power system is designed for a resonant frequency of 13.45 MHz. Also, a feedback WPT circuit to improve the power transfer efficiency is proposed and shown better performance than the original open WPT circuit, and the methodology for power efficiency improvement is studied as the coupling coefficient increases above 0.01, at which the split frequency is made.

Magnetic Wireless Power Transfer Antenna Using Ferrite (페라이트를 이용한 자기장 무선전력전송 안테나)

  • Ko, Nak-Young;Lee, Bon-Young;Song, Seong-Kyu;Park, Woo-Jin;Seo, Seok-Tae;Bien, Franklin
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.7
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    • pp.49-54
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    • 2017
  • In this paper, we propose magnetic field wireless power transfer antenna using Ferrite. It is possible to transfer magnetic field wireless power without independent ground by using characteristic of ferrite in the point that conventional magnetic field wireless power transfer was possible with independent grounding. Ferrite has a shielding effect of magnetic field and reduces leakage power, thereby improving transfer efficiency. We propose an antenna for magnetic field wireless power transfer using ferrite and confirmed that it is transmitted by 5W magnetic field wireless power through experiments. The wireless power transfer proposed in this paper can be applied variously to the Internet of things by using the magnetic field wireless power transfer through the metal.

Wireless Power Transfer Technologies Trends (무선전력전송에 대한 기술 개발 동향)

  • Eom, T.Y.;Oh, C.S.;Park, S.J.
    • Journal of Energy Engineering
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    • v.24 no.2
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    • pp.174-178
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    • 2015
  • We have surveyed on technical method of wireless power transfer and have also surveyed on applications of the wireless charging for mobiles and of the wireless charging for electrical vehicle and electrical equipments. In this study, we have described about wireless power transfer and have analyzed and checked wireless power transfer prospects of applications and practical development.