• Title/Summary/Keyword: Double Coil

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Double-Loop Coil Design for Wireless Power Transfer to Embedded Sensors on Spindles

  • Chen, Suiyu;Yang, Yongmin;Luo, Yanting
    • Journal of Power Electronics
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    • v.19 no.2
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    • pp.602-611
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    • 2019
  • The major drawbacks of magnetic resonant coupled wireless power transfer (WPT) to the embedded sensors on spindles are transmission instability and low efficiency of the transmission. This paper proposes a novel double-loop coil design for wirelessly charging embedded sensors. Theoretical and finite-element analyses show that the proposed coil has good transmission performance. In addition, the power transmission capability of the double-loop coil can be improved by reducing the radius difference and width difference of the transmitter and receiver. It has been demonstrated by analysis and practical experiments that a magnetic resonant coupled WPT system using the double-loop coil can provide a stable and efficient power transmission to embedded sensors.

Improved Degree of Freedom of Magnetic Induction Wireless Charging Coil Using Proposed Double Coil (이중코일을 이용한 자기유도 무선충전 코일의 자유도 개선)

  • Choi, Bo-Hee;Nam, Yong-Hyun;Chung, Habong;Lee, Jeong-Hae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.12
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    • pp.907-914
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    • 2018
  • Wireless charging has been actively researched and popularized owing to the potential convenience of being able to charge electronic devices without wires for users. However, the receiver on the wireless charging pad is not charged when the center of the receiver is misaligned; thus, the center of the receiver must be adjusted well. This misalignment may greatly reduce the convenience of wireless charging. To overcome this limitation of wireless charging, a coil is designed to improve the positional freedom of the receiver. The positional freedom of the Rx coil is improved when the outer diameter of Tx coil is larger than when Rx and Tx coils are almost the same size. When the Tx coil has a larger outer diameter than that of the Rx coil, the efficiency at the center is somewhat lowered, but the efficiency is improved compared to when the center is out of order. In this paper, a double coil structure having an outer and an inner coil is proposed. The double coil structure further improves the efficiency, compared with one coil with the same outer size. The simulation and measurement results demonstrated that the tendency was consistent, and it was verified that the degree of freedom of the Rx coil is improved by adding the inner coil, while the size of the outer coil was the same. The measurement shows that the transmission efficiency of the conventional Tx coil is 37 %, the larger outer diameter coil is 45 %, and double coil is 47 % when the distance of the Tx/Rx coil is 3 mm, the misalignment is 15 mm and current flowing in the Rx coil is 1 A at an operating frequency of 105 to 210 kHz.

Dielectric Insulation Properties of Double Pancake Coil Type HTS Transformer (Double Pancake Coil형 고온초전도 변압기의 전기적 절연 특성)

  • 백승명;정종만;이현수;한철수;김상현
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.2
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    • pp.151-156
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    • 2003
  • High temperature superconductor can only be applied against an engineering specofication that has to be determined for each particular application form the design requirements for economic viability and for operation margins in service. However, in order to realize the HTS transformer, it is necessary to establish the high voltage insulation technique in cryogenic temperature. Therefore, the composite insulation of double pancake coil type transformer are described and AC breakdown voltage characteristics of liquid nitrogen(LN$_2$) under HTS pancake coil electrode made by Bi-2223/Ag are studied. The Breakdown of LN$_2$ is dominated electrode shape and distance. The influence of pressure on breakdown voltage is discussed with th different electrode. For the electrical insulation design of turn-to-turn insulation for the HTS transformer, we tested breakdown strength of insulation sheet under varying pressure. And we investigated surface flashover properties of LN$_2$ and complex conition of cryogenic gaseous nitrogen(CGN$_2$) obove a LN$_2$ surface. The surface voltage of GFRP was measured as a function of thickness and electrode distance in LN$_2$ and complex condition of CGN$_2$ above a LN$_2$ surface. this research presented information of electrical insulation design for double pancake coil(DPC) type HTS transformer.

Breakdown Properties for Electrical Insulation Design of Double Pancake Coil Type HTS Transformer (Double Pancake Coil형 고온초전도 변압기의 전기적 절연 설계를 위한 절연파괴 특성)

  • Baek, Seung-Myeong;Jung, Jong-Man;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.08a
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    • pp.52-57
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    • 2002
  • High temperature superconductors can only be applied against an engineering specification that has to be determined for each particular application form the design requirements for economic viability and for operation margins in service. However, in order to realize the HTS transformer, it is necessary to establish the high voltage insulation technique in cryogenic temperature. Therefore, the composite insulation of double pancake coil type transformer are described and ac breakdown voltage characteristics of liquid nitrogen($LN_{2}$) under HITS pancake coil electrode made by Bi-2223/Ag are studied. Breakdown in $LN_{2}$ is dominated electrode shape and distance. And we investigated AC breakdown properties of $LN_{2}$ and complex conition of cryogenic gaseous nitrogen($CGN_{2}$) obove a $LN_{2}$ surface. Also, the surface voltage of GFRP was measured as a function of thickness and electrode distance in $LN_{2}$ and complex condition of $CGN_{2}$ above a $LN_{2}$ surface. This research presented information of electrical insulation design for double pancake coil type HTS transformer.

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Dielectric Insulation properties of Double Pancake coil type HTS Transformer (Double Pancake형 고온초전도 변압기의 전기적 절연 특성)

  • 백승명;정종만;이정원;김상현
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.494-498
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    • 2002
  • HTS transformer experimentally. High temperature superconductors can only be applied against an engineering specification that has to be determined for each particular application form the design requirements for economic viability and for operation margins in service. High temperature superconducting(HTS) power apparatus are very promising candidates for application. Especially, these advantages make superconducting transformers very promising candidates for application in electrical power engineering and locomotives. In order to realize the HTS transformer, it is necessary to establish the high voltage insulation technique in cryogenic temperature. So far, insulation research of Pancake type HTS transformer is lacking nothing but insulation research of . solenoid type transformer consisted. Therefore, the composite insulation of double pancake coil type transformer are described and ac breakdown voltage characteristics of liquid nitrogen(LN$_2$) under HTS pancake coil electrode made by Bi-2223/Ag are studied. Breakdown in LN$_2$ is dominated electrode shape and distance. The relation between surface flashover voltage is considered for FRP. This research presented basis information of electrical insulation design for double pancake coil type HTS transformer.

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Test Results of a Three Phase 10㎸A HTS Transformer With Double Pan Cake Coils (3상 10kVA 더블 팬케익 코일형 고온초전도 변압기 특성시험 결과)

  • 이승욱;이희준;차귀수;이지광;최경달;류경우;한송엽
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.3
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    • pp.101-106
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    • 2003
  • The high temperature superconductor transformers gain interests from the industries. This paper described construction and test results of 10㎸A HTS transformer Three phase transformer with double pancake windings were constructed. To reduce the leakage magnetic field, secondary coil were placed between the two primary coils. BSCCO-2223 wire. silicon sheet steel core and FRP cryostats were used to construct the transformer. Three coils were stacked in one cryostat. Two double pancake coils were connected in series for the primary coil and one double pancake coil was used for the secondary coil. Total number of turns of the primary winding and the secondary winding were 112turns and 98urns, respectively, The rated voltages of each winding were 440/220V. The rated currents of each winding were 13.1/26.2A. After the tests of basic properties of the three phase HTS transformer using no-load test, short-circuit test and full-load test, continuous operation of 100 hours with pure resistive load has been carried out. Test results proved over-load capability and reliability of the HTS transformer.

Design of Crisscrossed Double-Layer Birdcage Coil for Improving B1+ Field Homogeneity for Small-Animal Magnetic Resonance Imaging at 300 MHz

  • Seo, Jeung-Hoon;Han, Sang-Doc;Kim, Kyoung-Nam
    • Journal of Magnetics
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    • v.20 no.3
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    • pp.308-311
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    • 2015
  • We design a crisscrossed double-layer birdcage (DLBC) coil by modifying the coil geometry of a standard single-layer BC (SLBC) coil to enhance the homogeneity of transmitting magnetic flux density ($B_1{^+}$) along the main magnetic field ($B_0$)-direction for small-animal magnetic resonance imaging (MRI) at 300 MHz. The performance assessment of the crisscrossed DLBC coil is conducted by computational analysis with the finite-difference time domain method (FDTD) and compared with SLBC coil in terms of the $B_1$ and the $B_1{^+}$ distribution. As per the computational calculation studies, the mean value in the two-dimensional $B_1{^+}$ map obtained at the mid-axial slice with the proposed DLBC coil is slightly lower than that obtained with the SLBC coil, but the $B_1{^+}$ value of the DLBC coil in the outermost plane (40 mm away from the central plane) shows improvements of 19.3% and 24.8% over the SLBC coil $B_1{^+}$ value when simulating a spherical phantom and realistic mouse body modeling. These simulation results indicate that, the $B_1{^+}$ homogeneity along the z-direction was improved by using DLBC configuration. Our approach enables $B_1{^+}$ homogeneity improvement along the zdirection, and it can also be applied to ultra-high field (UHF) MRI systems.

Fabrication and Properties of HTS Double Pancake Coils (고온초전도 더블 팬케이크 코일 제작 및 특성)

  • 손명환;이언용;백승규;권영길;윤문수;권용덕
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.263-265
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    • 2003
  • A winding machine to fabricate the double pancake coils was manufactured. A race-track type double pancake coil using high temperature superconductor (HTS) tape was prepared and I-V and I-H characteristic curves were obtained at the atmosphere of liquid nitrogen. The winding method to make the double pancake coil and its properties is discussed.

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The Prediction of Nonlinear behavior of Double Coil Shape Memory Alloy Spring (이중 나선 구조 형상기억합금 스프링 거동 예측)

  • Lee, Jong-Gu;Ahn, Sung-Min;Cho, Kyu-Jin;Cho, Maenghyo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.4
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    • pp.347-354
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    • 2012
  • The recovery force and displacement occur due to the phase transformation from the martensite phase to the austenite phase induced by the mechanical loading or thermal loading. These recovery force and displacement depend on an initial geometrical configuration of SMAs and loading conditions. Although the SMAs generally generates large recovery forces, the sufficient recovery displacement cannot be expected without a proper design strategy. The functionality of SMAs is limited due to the unbalance between the large recovery force and the small recovery displacement. This study suggests the double coil SMA spring in order to amplifying the recovery displacement induced by the phase transformation. By predicting the recovery displacement of doble coil SMA springs and one coil SMA springs induced by thermal loading, we show that the double coil SMA spring not only mitigate the unbalance of performance but also have a large recovery displacement for its recovery force than one coil SMA spring.

Double-Excitation Type Single Sheet Tester for the Measurement of the Magnetic Characteristics of the Electrical Steel Sheets (전기강판의 자기특성 측정을 위한 2방향 여자 형 Single Sheet tester 개발)

  • Kim, Hong Jung;Koh, Chang Seop;Hong, Sun-Ki;Shin, Pan Seok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.10
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    • pp.461-469
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    • 2005
  • In this paper, a double-excitation type single sheet tester is developed to measure the magnetic characteristics of the electrical steel sheets. The developed system has the uniform magnetic field area of 20$\times$20mm$^{2}$, and can be applied to the measurement of the magnetic characteristics of the Non-oriented and Grain oriented electrical steel sheets. In the developed system, the magnetic flux density and magnetic field intensity are measured by using B-coil and H-coil, respectively. The B-coil has 1 turn search coil for each direction, and H-coil has 640 and 640 turns for rolling direction and transverse direction on the Im thickness Glass-Epoxy basement, respectively. Through experiments, it Is shown that the system can measure the magnetic characteristics up to 1.87 of magnetic flux density in the rolling direction in case of the Grain oriented electrical steel sheet. The measured results are compared with those measured in Okayama university, .Japan.