• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.294-295
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• 2005

다중 코어를 이용한 대전류 변압기용 Mn-Zn ferrite를 제조하고 전자기적 특성을 분석하였으며, 제조된 자심재료를 이용하여 변압기를 제조하고 전원장치에 탑재하여 효율특성을 분석하였다. ZnO의 몰비가 증가할수록 혼합 스피넬의 형성을 통한 보아 자자의 증가로 인해 투자율은 증가하고 상대적으로 전력손실이 감소하여 $Fe_2O_3$ : MnO : ZnO = 53 : 36 : 11 mo\% 일 때 가장 우수한 특성을 나타냈고, 열처리 공정의 승온 과정에서부터 산소 분압을 제어하고 최적의 대기압 상수를 산출함으로써 Zn-loss 현상을 최소화하여 ZnO 11 mol%, 대기압 상수 7.7일 때 투자율 2350, 밀도 4.9 $g/cm^3$, 비저항 480 ${\Omega}cm$, 300 mT의 최대 자속 밀도 특성을 갖는 우수한 자심 재료를 개발하였다. 그리고 최소 손실 온도를 $90^{\circ}C$ 이하로 감소시켰으며 100 kHz에서 250 $kW/m^3$의 낮은 전력손실을 나타냈다. 또한 개발된 자심재료를 이용하여 제조된 전원장치는 30~80A의 출력 전류에서 85% 이상의 고효율을 얻었다.

• Resources Recycling
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• v.8 no.4
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• pp.45-56
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• 1999

The purpose of tlus sludy was to preparc raw material powder for Mn-Zn iclrile, h m mined mill scale and fero-Mn, usins a co-spray roasting process The mill scale and ferra-Mn uscd in this raalins process was rcf~nedb y mesn-ns of a slxc~apl rxcss ~nvolvinm~a te~ialsc ontalning imp~u-ltleso r less than 100 pprn In this study an effeclive spray roaster system. wllich produces fme complex oxide powder, collects produccd ~owder.,m d prcvel~tse ~~llssiooifi HCI gas. was also manufactured. By means of spray~ngp urifcd raw malerial solu~lionl nln a manufacued high tcmpervture rumace. &-ferrite powder and a comnpleu o ~ d e powder of Fe,O; and M,x203 were manufactured. The chmcterlstics of the composllion. surface urca, and p'miicle size dismbulion or the produced powder were exmined. ptoduced powdcr was then ~ m e dwi tli ZnO powder. aid olher addilives of defined cornposnion, and Mn-Zn femite cares werc praiuccil by meuns of Sorlning and closely controlled sintering processes. The magpelic p~oprlieso f c olo~ss, initlal permeability. mauin~u~mnn agnehc flux. coz~civcr orcc and residual magnccic flux for the above cores we,= measured, and fmm Il~ase I-csulls the eflicacy of lhe co-spray roasling pncess to pl.ellare raw material powder lor Mn-Zn ferntc was established

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.5
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• pp.703-711
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• 2013

In this paper, we have proposed high power generator with Induction Voltage Adder of three cells. IVA which has n cells can generate n-th times high power pulse, is a more stable system than Marx generator in the view of breakdown. We applied amorphous metal magnetic cores as an energy storing material for IVA rather than ferrite cores because of their higher magnetic flux swing to make it more compact system and the loss of it was also considered in the design. For driving the IVA, we design Blumlein pulse generators which are filled with pure water for high dielectric constant and high breakdown field strength, and triggered by single Marx generator. We have presented the PSPICE simulation and its test result.

• Journal of the Korean Magnetics Society
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• v.22 no.1
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• pp.23-26
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• 2012

New digital feedback algorithm was developed to measure iron loss of soft magnetic materials under a condition of sinusoidal flux waveform. $V_{in}$(B) curve was used instead of H(B) curve to decide next input waveform in the feedback module so that adjusting phases of current waveform, flux waveform, and input waveform could be removed. The effectiveness of the developed algorithm was verified when iron loss of ferrite cores was measured under frequencies of 1 and 10 kHz.

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

• Journal of the Korean Ceramic Society
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• v.34 no.6
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• pp.561-568
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• 1997

The effects of sintering temperature and oxygen partial pressure on the electromagnetic properties of Mn-Zn ferrites were investigated. The grain increased with increasing temperature. The power loss at 100 kHz was decreased, while the power loss at 500 kHz was increased as the grain size increased with sintering temperature. Sintering with low oxygen partial pressure at 115$0^{\circ}C$ resulted in high density and initial permeability, and decreased the power loss at 100 kHz and 500 kHz. The oxygen partial pressure lower than 10-2 atm. during heating, significantly suppressed the hysteresis loss. However, the oxygen activity did not affect the grain size of sintered cores.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.23-26
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• 2003

The flat transformer, typically, has a number of parallel single turn secondary windings. Each secondary winding is coupled to the same primary winding. Therefore, the current in each secondary winding is equal to the ampere-turns in the primary winding, and to each other. These characteristics are particularly advantageous where parallel rectifiers are used. The windings share the current equally, with no need for ballast resistors or other added components. In this study, the ferrite magnetic core samples of Mn-Zn system for the Flat transformer are manufactured and the electrical and magnetic characteristics of its tested. The density of sample FO2-2 sintered at $1350^{\circ}C$ is $4.00kg/m^3$, which shows the good microstructural state. The initial permeability and saturation flux density of FO2 at room temperature is 2700 and 510mT, individually. The power loss of FO2 samples at 250kHz have been ranged $350kW/m^3$ to $80kW/m^3$ with temperature. And the minimum power loss of sample FO2-2 showed at $70^{\circ}C$, which property seems very positive to apply for a flat transformer.

• Journal of the Korean Magnetics Society
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• v.9 no.3
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• pp.149-153
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• 1999

Frequency and temperature dependence of magnetic loss has been investigated in Mn-Zn ferrites containing the sesistive temary compounds of $SiO_2-CaO-V_2O_5$. The Mn-Zn ferrite with the composition of $MnO:ZnO:Fe_2O_3=36:11:53$(by mol %) are prepared by self-propagating high-temperature synthesis. From the results of frequency dependence of core loss, it has been found that the hysteresis loss is dominant at low frequency and the eddy current loss becomes more dominant as the frequency increases. With the addition of resistive compound, the frequency dependence of core loss, it has been found that the hysteresis loss is dominant at low frequency and the eddy current loss becomes more dominant as the frequency increases. With the addition of resistive compound, the frequency region where the hysteresis loss is dominant becomes wide. The core-loss minimum occurs at about 4$0^{\circ}C$ in the specimens with the additive because of the reduction in eddy current loss.

• Journal of IKEEE
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• v.23 no.2
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• pp.599-605
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• 2019

Ferrite cores are used as a soft magnetic material in the fabrication of couplers for inductive powerline communication (PLC). However, it is difficult to adjust the size freely according to the power-line and power-grid environment. In this paper, we report that a nano-crystalline alloy with higher permeability than ferrite can be used as an inductive coupler for non-contact PLC. Since nano-crystalline are produced in the form of a thin ribbon, the size of the coupler can be freely controlled by the number of ribbons wound on the toroidal core. It was fabricated with induction type coupler and showed to be suitable for non-contact power line communication. Experimental results show that the communication bandwidth is 45 Mbps for 100 m and 8 Mbps for 200 m under the current fluctuation of less than 100 A, and the reception ratio is 100%.

• Resources Recycling
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• v.11 no.5
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• pp.34-38
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• 2002

To minimize the size of transformer volume, the operating frequency of ferrites cores increasing. The power loss of Mn-Zn ferrites comprises hysteresis loss, eddy current loss and residual loss. In the range more then 500 KHz, the total power loss is mainly due to the residual loss. The power loss increase with the frequency 3rd power. To minimize residual loss as well as eddy current loss, the microstructure should have small grain and high density, It should be noted that as the product of resonance frequency and static permeability increase, the power loss decrease at high frequency region.