• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.999-1004
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• 2011

In this paper, calculation method of mutual inductance for two circular coils which are widely used in wireless power transfer system and analysis results using the method are proposed. Two circular coils are arranged in a perpendicular way. For calculation of the mutual inductance, an Rx coil placed perpendicularly with the other coil is uniformly subdivided into many unit cells and both magnetic flux density linked with the Rx coil at each unit cell and the total magnetic flux density of the Rx coil are obtained. Two circular coils are considered as a filamentary coil and uniform current density on each coil is assumed. For verification, helical and spiral coils are fabricated. As a result of measurement in 50 cm to 100 cm distance, theoretical mutual inductance is almost agreed with measured one.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.3
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• pp.282-290
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• 2001

The accurate identification of the motor parameters is crucially important to achieve high dynamic performance of induction motors. In this paper, th motor parameters such as stator(rotor) resistance, stator(rotor) leakage inductance, mutual inductance, and rotor inertia are measured in off-line. Stator(rotor) resistance and stator(rotor) leakage inductance are measured based on the stationary coordinate equations of induction motors. On the other hand, mutual inductance are measured under the scalar control. Finally, the inverse rotor time constant is identified in on-line using an extended kalman filter algorithm. To demonstrate the practical significance of the results, Some experimental results are presented.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.948-949
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• 2015

일반적으로 IPMSM의 전압방정식은 d축과 q축이 90도의 위상차를 가지고 있기 때문에 d-q축 간의 상호 인덕턴스를 고려하지 않는다. 하지만 실제로는 d축의 인덕턴스는 q축 전류에 영향을 받으며, 반대로 q축의 인덕턴스도 d축 전류에 영향을 받는다. 따라서 비선형 모델링을 통해 실제 전동기의 형태에 더 가깝게 묘사 하였다. 또한 일반적인 수학식으로 계산하여 Ldq, Lqd를 구해 LPF 필터를 사용하였고 이산적인 최소자승법을 이용한 Gain값을 통해 과도상태에서 더 적합한 LPF와 최소자승법을 비교하는 논문이다.

• Journal of the Korean Magnetics Society
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• v.27 no.1
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• pp.9-17
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• 2017

A multi-phase electric machine has gained distinct interest due to its high reliability compared to a three-phase structure, and in this paper, self and mutual inductances in a five-phase permanent magnet synchronous machine (PMSM) are estimated by an analytical method. Recently, most of high-performance operations are implemented by field oriented control and/or direct torque control, and inductance for those controls is one of the key parameters in the voltage equation of phase windings. Winding function theory (WFT) is employed to calculate the inductance of phase windings, and it is verified that the result of the analytical method has a deviation of approximately 3 % compared to finite element analysis. Finally, in this paper, the way to obtain direct and quadrature inductance values are introduced from the analytical inductance calculated by WFT.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.41-46
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• 2011

The mutual inductances between power line and communication line above ground are studied in this paper. A long power line is discussed and the terminal effect above ground is taken into account. By applying Carson's method, the analytical solution to mutual inductances is derived and numerically evaluated. The analytical solutions derived in this paper are valid for both oblique and parallel proximity between power and communication lines, and the numerical results are compared with previous published results.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.21-26
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• 2009

In order to determine the effective way of measuring the Mode I stress intensity factor($K_1$) by means of the alternating current potential drop(ACPD) technique for a material containing a two-dimensional surface crack, the change in magnetic flux in the air due to load was studied theoretically and experimentally. The magnetic flux in the air between crack surfaces is uniform and is not changed by increasing the load in the specimen and experimental results are the same as those obtained from theoretical analysis. Therefore, the change in potential drop due to load in the measuring system which was designed to induce a large amount of electro-motive force was caused by the change in internal inductance of material and the change in the mutual inductance concerned with internal inductance of material.

• Journal of the Korean Magnetics Society
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• v.6 no.3
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• pp.179-188
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• 1996

This paper discussed on the impedance analysis of the planar air core inductors having spiral pattern and meander pattern. The width and distance of conductor, and number of turns were varied. As the width of conductor increased, both resistance and inductance decreased and there existed an maximum value in Q for spiral pattern. But Q increased with increasing width of conductor in meander pattern. In spiral pattern, there existed a distance between conductors where inductance became constant and Q became maximum, while the distance between conductors must be as large as possible to obtain large Q because the mutual inductance of meander pattern inductor has negative sign due to opposite current direction at adjacent conductor. Resistance and inductance increased with increasing the number of turns. There existed maximum Q at certain number of turns in spiral pattern. But Q became small in the meander pattern because increase of resistance was larger than increase of inductance with increasing number of turns.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.800-803
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• 2012

본 논문에서는 SATA(Serial Advanced Technology Attachment) 커넥터의 차동 임피던스를 정합하여 신호 전달 특성을 개선한다. 3차원 FEM(Finite Elements Method) 전자기장 시뮬레이터를 이용하여 SATA 커넥터의 차동 모드 S-파라미터를 추출하고, 신호 전달 특성을 분석한다. SATA 커넥터의 반사 손실 ($S_{dd11}$)은 5 GHz 까지 20 dB 이하의 값을 나타내고, 삽입 손실($S_{dd21}$)은 0.1 dB 이하의 값을 나타낸다. 또한 인덕턴스, 커패시턴스, 상호 인덕턴스, 상호 커패시턴스를 추출하여 차동 임피던스를 계산한다. SATA 커넥터의 차동 임피던스는 107.3 ${\Omega}$으로 부정합이다. 차동 임피던스를 정합하기위해서 커넥터 신호 핀을 dx 방향으로 설계 변경한다. $d_x$ 방향으로 0.04 mm 증가 시켰을 때 차동 임피던스가 99.5 ${\Omega}$으로 최적으로 정합되었다. 또한 반사 손실은 1.5 GHz 에서 11 dB 개선되고, 삽입 손실은 최대 약 0.05 dB 개선되었다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.90-92
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• 2019

본 논문은 GaN 디바이스를 사용하는 전력변환장치에서 Pick-up coil을 PCB 패턴으로 구현하여 전류를 측정하는 기법에 관하여 제안한다. 기존에 사용되는 PCB 패턴 코일 구조의 경우 PCB 이중층만 구성하여 관통 홀이나 추가공정이 필요함에 비해 본 논문에서 제안한 PCB 패턴 코일 구조의 경우 다층기판을 사용하여 코일을 구성함으로서 기존의 패턴에 비해 높은 상호 인덕턴스 값을 가지게 되고, 코일의 출력 전압값이 높아져 더 높은 감도를 가지게 된다. 또한 PCB 외부의 추가적인 공정 작업이 없이 구성이 되었다. 전류 측정은 코일 뒷단에 적분기를 통합하여 구성하였으며, 시뮬레이션을 통해 전류 측정 성능을 검증한다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.16-25
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• 2002

This paper presents a methodology and application for extracting parasitic inductances in a multi-level interconnect semiconductor structure by a numerical technique. In order to calculate the parasitic inductances, the distrubution of electric potential and current density in the metal lines are calculated by finite element method (FEM). Thereafter, the magneto-static energy caused by the current density in metal lines was calculated. The result of simulation is compared with the result of Grover equation about analytic simple structures, and 4 bit ROM array with a dimension of $13{\times}10.25{\times}8.25{\mu}m^3$ was simulated to extract the parasitic inductnaces. In this calculation, 6,358 nodes with 31,941 tetrahedra were used in ULTRA 10 workstation. The total CPU time for the simulation was about 150 seconds, while the memory size of 20 MB was required.