• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.204-207
• /
• 2000

In this paper, we have studied the effect of doped with B-Bi-Zn on properties (microstructure, density, shrinkage, permeability as a function of frequency, etc.) of hexagonal-ferrite for high frequency chip-inductor material about several GHz. The permeability were analyzed by impedance analyzer(100 kHz~40 MHz) and network analyzer(30 MHz~3 GHZ). As a result of the characteristics, the B-Bi-Zn glass ceramic was used to lower the sintering temperature for additive as a function of frequency from 100 kHz to 1.8 GHz showed constant tends. The maximum imaginary value of complex permeability was observed near the resonance frequency of 2 GHz.

• Journal of Electrical Engineering and Technology
• /
• v.6 no.4
• /
• pp.527-534
• /
• 2011

In the present paper, the characteristics of Mega-Flux$^{(R)}$, JNEX-Core$^{(R)}$, amorphous and ferrite cores are compared to the inductor of buck-boost converters for Hybrid Electric Vehicles. Core losses are analyzed at the condition of 10 kHz sine wave excitations, and permeability fluctuations vs. temperature and magnetizing force will be analyzed and discussed. Under the specifications of the buck-boost converter for 20 kW THS-II, the power inductor will be designed with Mega-Flux$^{(R)}$ and JNEX-Core$^{(R)}$, and informative simulation results will be provided with respect to dc bias characteristics, core and copper losses.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.5
• /
• pp.816-820
• /
• 2008

The RF inductive discharge of inductively couples plasma (ICP) continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. Although most practical ICPs operate at 13.56 [MHz] and 2.65 [MHz], the trend to reduce the operating frequency is clearly recognizable from recent ICP developments. In an electrodeless fluorescent lamp, the use of a lower operating frequency simplifies and reduces cost of RF matching systems and RF generators and can eliminate capacitive coupling between the inductor coil and plasma, which could be a strong factor in wall erosion and plasma contamination. In this study, We discussed simulation and experimental results when changing ferrite position in antenna.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.9
• /
• pp.467-475
• /
• 1999

This paper presents an analysis method of a forward converter, using both the finite element method considering the external circuit and a state variables equation. The converter operates at 50kHz and its one period is divided into two modes for the simplicity of the analysis. In the first mode, the switching transistor turns on and an input power is transferred into the load by the electromagnetic conversion action of a ferrite transformer. In the second mode, the switching transistor turns off and the stored energy in an inductor is delivered to the load, and the transformer core is demagnetized by the reset winding current. In this paper, time-stepping finite element method taking into account the on-state electrical circuit of the converter in used to analyze both the electrical circuit and electromagnetic field of the magnetic device during the first mode and the demagnetization period of the transformer core. Then a state variables equation for the circuit which the inductor current flows is constituted and solved during the second mode. As a result, the simulation results have been good agreement with the results obtained form experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.1168-1171
• /
• 2003

In contrast to a conventional transformer, the flat transformer is made using a number of small ferrite cores. Two cores for transformer and one core for inductor, which composed one module. Many modules can be connected together to form a flat matrix transformer. This structural arrangement eliminates the single hot spot problem in conventional transformers and permits high current density pertains at high frequency. In this study, the ferrite magnetic cores of Mn-Zn system for the Flat transformer were manufactured and the electrical and magnetic characteristics of its tested. The power loss of sample FO2(Mn-Zn ferrite) sintered at $1350^{\circ}C$ was $350kW/m^3$ in test conditions of 250kHz, 200mT and $100^{\circ}C$, which showed the good power loss property in high frequency. The power loss of FO2 samples has been studied as a function of magnetic flux density and frequency. Steinmetz exponent was 2.82 at 250kHz and 2.73 at 500kHz. These results illustrated the switching of power loss mechanism in ferrite core from hysteresis losses to eddy current losses or others.

• Journal of the Microelectronics and Packaging Society
• /
• v.3 no.1
• /
• pp.41-48
• /
• 1996

동시 소성으로 LCR network을 구성하기 위한90$0^{\circ}C$ 소성용 Ru계 저항체를 제조하 였다. 동시 소성에 요구되는 최종온도에 이르기 위해서는 90$0^{\circ}C$에서 용융되는 유리상을 제 조하는 것이 필수적이다. 이 90$0^{\circ}C$소결용 저항 페이스트는 가장 낮은 용융온도를 갖는 PbO 의 양을 감소시키고 알루미나와 실리카의 양을 증가시켜 제조하였다. 본 연구에서는 ferrite 로 이루어진 inductor 그린쉬트 위에 ruthenate 저항체를 인쇄하여 동시소성한후 그 복합체 의 저항 특서에대하여 고찰하였다. PbO의 양이 감소될수록 복합 기판의 면적저항은 증가 되었고 inductor 기판 위에 잔류되는 저항페이스트의 양도 함께 증가하였다.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.449-451
• /
• 2005

In this paper, to report the experimental results the core losses of VRM inductor. The VRM, that has a output voltage 1.5V, output current 60A, maximum power of 90W. Experimental results verify, the VRM has a almost same data of fast transient response, a efficiency test with high flux and ferrite inductor. A maximum power conversion efficiency of the experimental VRM was measured at 92% within 0.2% load regulation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.80-83
• /
• 1999

We have studied properties(crystal structure, density, absorption, contraction, initial permeability, and permeability) of Ni$_{0.175-x}$Cu$_{x}$Zn$_{0.33}$Fe$_{0.495}$ (x=0~0.175) ferrites with various NiO and CuO, because of development of materials for high frequency inductor. The XRD peaks of all of samples were observed only spine이 phase. As a results of the density, absorption rate, and shrinkage rate, the grain growth progressed rapidly in x=0.1 at 95$0^{\circ}C$, x=0.075 at 105$0^{\circ}C$, and x=0.025 at 115$0^{\circ}C$ for 3 hours. Initial permeability increased with increasing CuO concentration until x=0.1, and then decreased. The complex permeability as a function frequency were high values at sintered 105$0^{\circ}C$ fotr3 hours in x=0.075, 0.1., 0.1.1.

• Journal of the Korean Ceramic Society
• /
• v.36 no.3
• /
• pp.284-292
• /
• 1999

고체함량을 변화시킨 NiCuZn 페라이트 페이스트를 사용하여 스크린 인쇄법으로 7.7$\times$4.5$\times$1.0 nm 크기의 칩인덕터를 제조한 후, 페라이트 페이스트의 고체함량에 따른 수축률, 소결밀도, 미세구조, 계면반응 등의 물리적 특성 및 자기적 특성 변화를 분석하였다. 조온소결을 위하여 attrition milling 공정을 통하여 미세분말을 준비하였으며, 소결온도는 880~94$0^{\circ}C$로 변화시켰다. 90$0^{\circ}C$에서 2시간 열처리된 페라이트 후막의 소결밀도는 고체함량이 50,55,60%로 증가할수록 5.12,5.14,5.18g/㎤로 증가하였으며, 이에 따라 칩 인덕터 시편들의 주파수 10 MHz에서 L값이 2.1,2.3,2.5 $\mu$H로 커졌다.Q값은 소결밀도 증가에 의한 Q값 증가효과와 아울러 입자가 커짐에 따른 반대효과로 인하여 고체함량에 따라 87,90,94로 큰 변화가 없었다. 페라이트 페이\ulcorner의 고체함량 및 소결온도와 무관하게 Ag 성분의 페라이트 쪽으로의 확산현상은 나타나지 않았다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.03b
• /
• pp.46-46
• /
• 2010

In order to detect exact corona discharge point at stator winding of a rotating machine, an inductively coupled magnetic probe has been developed, which consists of U-shaped and truncated manganese ferrite inductor as a helix. The measured current intensity is somewhat higher than commercially developed probe. It has been shown that the measured intensity of proposed probe is suitable for manual localization as to off-line stator winding monitoring of rotating machine.