• The Journal of the Korea institute of electronic communication sciences
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• 제15권6호
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• pp.1175-1186
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• 2020

In this study, the problem is analyzed, and methods of improvement are presented. For evaluating the performance of the proposed EGT sensor, a complex environment test equipment has been developed to test both high temperature and vibration conditions at the same time. This equipment evaluates the accuracy and response time of the EGT sensor. In the results of the comparison test of the complex environment test equipment of heat and vibration, the existing sensor showed a carbonization problem, and the proposed sensor showed no problem. Therefore, it is expected that the improved EGT sensor will be able to be applied to various industrial fields, including gas turbines for power generation.

• Journal of the Institute of Electronics and Information Engineers
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• 제51권9호
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• pp.182-189
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• 2014

A tapped delay line time-to-digital converter (TDC) can be easily implemented using internal carry chains in a field-programmable gate array, and hence, its use is widespread. However, the tapped delay line TDC suffers from performance degradation because of differences in the delay times of dedicated carry chains. In this paper, a dual edge measurement method is proposed instead of a typical step signal to the delay cell to compensate for the performance degradation caused by wide-delay cells in carry chains. By applying a pulse of a fixed width as an input to the carry chains and using the time information between the up and down edges of the signal pulse, the timing accuracy can be increased. Two dedicated carry chain sites are required for the dual edge measurements. By adopting the proposed dual edge measurement method, the average delay widths of the two carry chains were improved by more than 35%, from 17.3 ps and 16.7 ps to 11.2 ps and 10.1 ps, respectively. In addition, the maximum delay times were improved from 41.4 ps and 42.1 ps to 20.1 ps and 20.8 ps, respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제21권6호
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• pp.117-125
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• 2007

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system. Therefor, this paper, consists of an isolated DC-DC converter to boost the fuel cell voltage 380[VDC] and a PWM inverter with LC filter to convent the DC voltage to single-phase 220[VAC]. Expressly, The fuel cell system which it proposes DC-DC the efficient converter used PWM the phase transient control law and it depended to portion resonance ZVS switching, loss peek voltage and electric current of realization under make schedule, switching frequency anger and the switch reduction. And mind benevolence it sprouted 2 in stop circuit and it added and a direct current voltage and the electric current where the ingredient is reduced in load side ripple stable under make whom it will be able to supply. Besides the efficiency of 92[%]is obtained over the wide output voltage regulation ranges and load variations. Also, under make over together the result leads simulation and test, the propriety confirmation.

• Journal of Navigation and Port Research
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• 제29권10호
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• pp.859-863
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• 2005

This paper describes the improvement of power control characteristics of ship's emergency lighting power supply(SELPS), by which electric power is controlled extensively, and power ON-OFF is controlled and system parameter monitored in remote distance by PC serial communication. Proposed system is composed of step-down converter(SDC), emergency power supply circuit(EPSC), half bridge(HB) inverter, fluorescent lamp(FL) starting circuit, microprocessor control and multi communication circuit. Experimental works confirm that relative system stops when over current is detected and speedy and stable emergency power is supplied when main power source cut-off, and controls input power up to 35[$\%$] by adjusting pulse frequency of the HB inverter, and ON-OFF control of multiple SELS, real time transmission and monitor of parameters as to voltage, current, and power values are performed appropriately by PC communication.

• Proceedings of the KIPE Conference
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.490-492
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• 2008

고압 전원 장치(High Voltage Power Supply)는 근래에 와서 산업전반에 응용이 매우 광범위하게 확산되고 있고 고전압 장치가 필수적으로 이용 되어야 하는 분야가 점차 확산되고 있다. 응용분야로는 신소재 개발과 플라즈마 응용을 위한 공업용과 민생용, 의료기기용, 군사용, 또한 프린터에 이르기까지 다양하게 있다. 가정이나 사무실에서 쉽게 접할 수 있는 IT장비인 프린터인 경우에도 전원 공급 장치의 측면에서는 화상형성에 있어 가장 필수적인 안정적이고 다기능을 가지는 고압 전원장치를 적용하고 있고, 수요 또한 증가하고 있다. 본 논문은 낮은 입력 DC전압에서 높은 음의 DC전압을 출력하는 높은 전환 비의 극성 반전 형 DC/DC 전력 변환 회로에 관한 것으로써, 하나의 스위치, 하나의 인덕터, 그리고 다수개의 캐패시터와 다이오드로 구성된다. 기존의 극성 반전 형 DC/DC 컨버터 회로와 비교하여, 고압 변환 트랜스포머 대신에 인덕터를 사용할 수 있어, 자기 소자의 부피 및 크기는 물론 원가저감이 가능하다. 또한 반도체 소자의 Voltage Stress가 감소된다. 제안된 회로의 원리를 분석하고, 종래의 고압 전원장치와 비교함으로써 장점을 알아본 후, 동작원리에 대한 타당성을 Simulation 및 실험을 통하여 검증한다.

• The Transactions of the Korean Institute of Power Electronics
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• 제16권4호
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• pp.405-414
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• 2011

Recently, the development of several hundreds of kW scale PCS for fuel cell generation is required as commercialization process of distributed generation systems using high temperature fuel cells such as MCFC begins. This paper proposes and optimized topology suitable for MCFC fuel cell generation system and LCL filter design method considering voltage quality of local loads such as MBOP. An interleaving technique is applied to step-up DC-DC converter, optimized number of phases is determined considering efficiency and volume. Also, a LCL filter design method is proposed considering quality of current injected to the grid as well as that of voltage across the local load. The proposed PCS system is validated through reduced 1kW prototype.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제20권9호
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• pp.843-852
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• 2009

In this paper, we present design, fabrication, and measured results for a frequency upconverter for a wireless communication system of UAV(Unmanned Aerial Vehicle). The specifications of such wireless communication system requires the special features of maximum range of communication as well as deployment in UAV and repairing. The frequency upconverter operating at $5.25{\sim}5.45\;GHz$ in C-band was designed and fabricated considering such special features. The AGC function was included because the required output power should be constant for optimal system operation. The fabricated upconverter showed a constant output power of $+2{\pm}0.5\;dBm$ for the $-15{\sim}-10\;dBm$ input. Spuriouses were below -60 dBc and the adjacent leakage power was below -40 dBc. In addition, LO sources in the upconverter was implemented using the frequency synthesizer with step 1 MHz. This is for the application to the situation where multiple UAVs employed and the possible change of the permitted frequency band. The synthesizer showed a phase noise of -100 dBc/Hz at the 100 kHz frequency offset.

• Journal of the Korean Society for Nondestructive Testing
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• 제25권1호
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• pp.15-19
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• 2005

Conventional eddy current testing has been used for the detection of the defect-like fatigue crack in the conductive materials, such as aluminum, which uses a sinusoidal signal with very narrow frequency bandwidth, Whereas, the pulsed eddy current method uses a pulse signal with a broad bandwidth. This can allow multi-frequency eddy current testing, and the penetration depth is greater than that of the conventional eddy current testing. In this work, a pulsed eddy current instrument was developed for evaluating the metal loss. The developed instrument was composed of the pulse generator generating the maximum square pulse voltage of 40V, an amplifier controlled up to 52dB, an A/D converter of 16 bit and the sampling frequency of 20 MHz, and an industrial personal computer operated by the Windows program. A pulsed eddy current probe was designed as a pancake type in which the sensing roil was located inside the driving roil. The output signals of the sensing roil increased rapidly wich the step pulse driving voltage かn off, and the latter part of the sensing coil output voltage decreased exponentially with time. The decrement value of the output signals increased as the thickness of the aluminum test piece increased.