• Journal of Power Electronics
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• 제9권1호
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• pp.18-25
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• 2009

Conventional series-resonant pulse frequency modulation controlled DC-DC high power converters with a high-frequency transformer link which is designed for driving the high power microwave generator has the problem of hard switching commutation at turn-on and turn-off of active power switching devices. This problem is due to the influence of the magnetizing current of the high-frequency transformer. This paper presents a novel prototype for a high-frequency transformer using parasitic parameters with a lossless inductive snubber and a series resonant capacitor assisted series-resonant zero current switching pulse frequency modulated DC-DC power converter, which is designed using a high power magnetron for microwave ovens. In order to implement a complete and efficient soft switching commutation, the performance of the new converter topology is practically confirmed and evaluated in the prototype of a power microwave generator.

• 한국군사과학기술학회지
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• 제25권5호
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• pp.539-544
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• 2022

This research shows the test performance of a 6 kW-scale hybrid electric power system for the high endurance drone. The power system is composed of a two-stroke reciprocal engine, starter-generator and battery, and they are integrated as one power unit. The engine is designed to provide the house for holding the starter-generator at the end of a crankshaft in turn the engine and starter-generator can maintain the same speed during the operational period. In this way, the generated power is readily controlled by just manipulating an engine throttle movement. Moreover, the starter-generator can initiate an engine operation with an aid of battery power until the combustion process becomes stabilized. In consequence, integration mechanism between an engine and generator is simplified, which results in weight reduction achieved. The duty of back-up battery is to provide a starting power to generator via a system controller in addition to covering momentarily power shortage. Therefore, the electric power system is vindicated to provide 6 kW power through a ground test.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1349-1354
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• 2014

This paper presents a compact and portable high-voltage generator based on magnetic-core Tesla transformer for driving an UWB high power electromagnetic source. In order to optimize the performance of the high-voltage generator, a novel open-loop cylindrical magnetic-core adopting the quad-division lamination structure is proposed and manufactured. The designed high-voltage generator using the proposed magnetic core has a battery-powered operation and compact size of $280mm{\times}150mm$ in length and diameter, respectively. The high-voltage generator can produce a voltage pulse waveform with peak amplitude of 450 kV, a rise time of 1.5 ns, and pulse duration of 2.5 ns at the 800 V input voltage.

• 한국군사과학기술학회지
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• 제16권5호
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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.

• 전력전자학회논문지
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• 제8권2호
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• pp.192-198
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• 2003

본 논문에서는 의료 진단용 40kw(125kV, 80mA)급 X-선 전원 장치에 대하여 연구하였다. 의료 X-선용 고전압 발생 장치의 구성과 X-선 관전압과 관전류 그리고 피폭량 제어에 대하여 기존 제어 방식과 비교 설명하였고 제어기 설계시 고려할 사항에 대하여 언급하였다. 또한, 본 시스템의 핵심이라 할 수 있는 고주파 고전압 변압기의 등가회로를 통한 기생 성분에 대하여 기술하였으며 본 연구에서 제작된 의료 X-선용 HFG 시스템의 출력특성의 우수성을 X-전관 부하 변동에 따른 X-선 관전류와 관전압 파형을 통하여 입증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권1호
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• pp.34-39
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• 2002

Most X-ray generator had been used do rectifier type transformer high tension generator which is supplied in a clinical diagnosis. But it is difficult to miniaturize and become light weight. Also, because the ripple rate of tube voltage is high, X-ray generating efficiency is very low. Therefore, it is supplied gradually from abroad being developed high tension generator for inverter type X-ray generator which use semi-conductor switching element for electric power that have high speed switching ability to solved these problem. But, semi-conductor element of big capacity are used by X-ray tube's big consumption power and diffusion is difficult in the small size hospital because production cost is ascending by doing digital control through DSP and product price becomes expensive. Therefore, in this paper, design and manufactured CR type voltage divider for feedback control of tube voltage of high frequency resonance type inverter and high tension transformer for high frequency to apply economical diffusion type X-ray generator which have wide output voltage and load extent. It is Proved do X-ray generator and stability of X-ray tube's output characteristics through an experiment.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.121-121
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• 2010

As the industrial technology is getting higher, the pulsed power technology is required from various fields such as thermonuclear fusion energy sources, military applications, electric power distribution, and a variety of new specialized needs. This technology deals with the generation of very high power electromagnetic pulses through fast switching. We fabricated a pulsed power generator, named EMD pulse generator, by using Marx circuit with 200 kV high, 50 ns fast rise time. In this paper, we described about an effect of stray capacitance of coaxial Marx generator, EPG-AM200k, and a comparing the results of experiments and circuit analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.687-689
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• 2003

Recently, issues regarding environment and the diversification of dependence in oil are watched with keen interest. Wind power attracts most interest because of its high-energy efficiency with environment friendly functions. The paper discusses the development of a coreless axial-flux permanent magnet (AFPM) generator for a wind power system. Analyzed the Coreless AFPM generator by electromagnetic, and designed wind power generator with this. The 3 phase output of stator is rectified and fed to a common do link. The overall machine structure has high compactness and lightness, because of the lack of the iron core. The test results with a resistive load confirm the satisfactory operation of generator. Compared with conventional generator, the design has lower weight, lower Power loss and improved efficiency.

• 한국군사과학기술학회지
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• 제22권1호
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• pp.60-71
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• 2019

Electrical power supply is needed to operate the radar system in the field. In addition, it should not cause performance deterioration under the environmental factors due to characteristics of military equipment, and should not cause malfunction due to electromagnetic waves generated in radar, and then should not cause malfunction in radar equipment. Therefore, By applying a permanent magnet to the rotor of the generator, light weighting and high efficiency of generator were achieved. As a result, electrical performance test of the generator, the rated output power was 80.8 kW, the maximum output power was 88.1 kW, and the output power efficiency was 98.1 % under the full load condition. When the load capacity of the generator was changed from no load to full load, the maximum voltage variation was 3.6 % and the frequency variation was 0.3 %. As a result of the transient response test for measuring the output power of the generator according to the load characteristics change, the maximum voltage variation of 7.9 %, frequency variation of 0.5 % were confirmed, and the transient response time was 2.1 seconds. Environmental tests were conducted in accordance with MIL-STD-810G and MIL-STD-461F to evaluate the operability of the generator groups. Normal operation of radar system generator group was confirmed under high temperature and low temperature environment conditions. Electromagnetic tests were conducted to check if electromagnetic wave generated from both radar system and generator group in operation caused any performance deterioration to each other. As a result, it was confirmed that the performance deterioration due to electromagnetic wave inflow, radiation, and conduction did not occur. It is expected that it should be possible to provide high efficiency power supply and stable power supply by applying to various military system as well as radar system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1132-1135
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• 2008

The sludge grown up in steam generators of nuclear power plants shortens the life-cycle of steam generators and reduces the output of power plants. So KHNP(Korea Hydro and Nuclear Power), the only nuclear power utility in Korea, removes it periodically using a steam generator lancing system during the outage of plants for an overhaul. KEPRI(Korea Electric Power Research Institute) has developed lancing systems with high pressured water nozzle for steam generators of nuclear power plants since 2001. In this paper, the design of a partial inter-tube lancing system for model F type steam generators will be described. The system is actuated without a DC motor inner steam generators because the motors in a steam generator make a trouble from high intensity of radioactivity as a break down.