• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2237-2246
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• 2017

A nonisolated two-phase bidirectional dc-dc converter (NTPBDC) is a very attractive solution for the battery energy storage system (BESS) applications due to the high voltage conversion ratio and the reduced conduction loss of the switching devices. However, a hard-switching based NTPBDC decreases the overall voltage conversion efficiency. To overcome this problem, this paper proposes a novel NTPBDC with zero-voltage-transition (NTPBDC -ZVT). The soft-switching for the boost and buck main switches is achieved by using a resonant cell, which consists of a single resonant inductor and four auxiliary switches. Furthermore, due to the single resonant inductor, the proposed NTPBDC-ZVT has the advantages of simple implementation, reduced size, and low cost. The validity of the proposed NTPBDC-ZVT is verified through experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.159-163
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• 2001

A new and high-efficient energy-recovery circuit is proposed to drive a Plasma display panel (PDP) and compared with the conventional circuit. The Proposed circuit uses only two inductors and no auxiliary circuit to recover the energy stored in the equivalent intrinsic capacitance of Plow DP so that it feartures a very simple structure, small volume, fewer power devices. production cost and high efficiency. Besides, the light emitted from PDP is very stable and uniform. It is suitable for wall-hanging color TVs. The proposed circuit, operating at 200kHz, is verified to be applicable on a 42-inch PDP by an experiment.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.137-140
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• 2007

We consider the optimum air flow channel design for DMFC's in the present study. The effect of pressure drop across the inlet and outlet of a stack on the performance of a DMFC is the optimization of such geometric parameters is crucial to minimize the parasitic power usage by the auxiliary devices such as fuel pumps and blowers. In this paper, we present how the pressure drop control can optimize the driving point of a DMFC stack. Further, we show how the optimal fuel utilization ratio can be achieved, not degrading the performance of DMFC stacks. Overall, we discuss how the flow channel design affects the selection of balance of plant(BOP) components, the design of DMFC systems and the system efficiency.

• 한국산업융합학회 논문집
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• 제5권3호
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• pp.255-260
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• 2002

Recently, the occurrences of electrical fire have been suppressed by an earth leakage breaker(ELB), a no fuse breaker(NFB) and a fuse in case of an earth leakage, a short circuit and an over current. But it is impossible for the ELB to break the circuit in the case of the failure of pressure contacts on connecting points and the momentary short circuit. Therefore, it is require to study the constructive problem of the ELB. In this paper, we have developed the auxiliary control device, electrical fire prevention control device(EFPCD), of the ELB. And we have tested the operation characteristics of the ELB according to the load(R, L) As a result of this experiment, we could prevent the electrical fire due to the spark and the overheat occurring in the failure of pressure contacts on connecting points and the momentary short circuit.

• Industrial Engineering and Management Systems
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• 제13권4호
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• pp.408-413
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• 2014

The QWERTY type keyboard is a classical device that has been used for computers for a long time. The keyboard design of mobile devices like smartphones is an important issue to consider because of the limited space on the touch screen. This paper presents a design for symbol allocation on the QWERTY type soft keyboard. A 27-cell model, including the full stop (.), is proposed in this paper. A QWERTY type keyboard for smartphones is mainly known for its spatial compatibility, whereas the characters of the ANSI keyboard are allocated to the shoulder positions for functional auxiliary input methods such as the long pressing method.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1835-1841
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• 2017

An improved single-phase full-bridge zero-voltage-switching inverter using a subtractive coupled magnetics is proposed in this paper. The proposed topology overcomes several drawbacks of the conventional ARCPI zero-voltage-switching inverter including two bulky capacitors which can cause problems such as the need for a protection circuit and voltage fluctuation of split capacitors. Also the proposed topology can reduce the number of devices required for ZVS through a simplified auxiliary circuit, thus achieving low cost and small volume and is applicable a modified unipolar PWM scheme. Detail mode analysis and design considerations are provided for optimal efficiency. In the end, the effectiveness and feasibility of the proposed topology are verified experimentally under various conditions.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권2호
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• pp.80-86
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• 2003

In this paper, a new three-phase voltage-source inverter topology for high voltage and high Power applications is proposed to improve the quality of output voltage waveform. A chain converter which is used as an auxiliary circuit generates a ripple voltage and injects it to the conventional 12-step inverter. Thus, the injection of the ripple voltage results in 36-step operation with a link and 60-step operation with two links. The proposed inverter is compared to the conventional multilevel inverter in the viewpoint of ratings of phase- shifting transformers, switching devices and capacitors employed. The proposed scheme is simple to control capacitor voltages compared to the conventional schems and is cost effective for high voltage and high power application over several tens of MVA. The proposed approach is validated through simulation, and the experimental results are provided from a 2KVA laboratory prototype.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.1073-1075
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• 2001

The nitrogen oxides, NO and NO2, abbreviated usually as NOx, emitted from combustion facilities such as power plants and automobiles are the typical air-pollutants causing acid rain and photochemical smog. In order to solve the NOx-related pollution problems effectively, we need efficient techniques to monitor NOx in the combustion exhausts and in environments. Development of solid-state electrochemical devices for detecting NOx is demonstrated based on various combination of solid electrolytes and auxiliary sensing materials. The object of this research is to develop various sensor performance for solid state amperometric sensor, and to test gas sensor performance manufactured. So we try to present a guidance for developing amperometric gas sensor. We concentrated on development of manufacturing process and performance test.

• 한국도서관정보학회지
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• 제40권2호
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• pp.5-26
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• 2009

이 연구는, KDC 5판에서 문제점들이 다수 발견되어 시스템으로서의 문헌분류법에 부합하는 표준적인 조건을 제시한 다음, KDC 5판을 대상으로 각종 표준적인 조건에의 부합 여부를 자세하게 진단하여 발견된 구체적인 문제점들에 대한 합당한 처방을 마련 제시함으로써 향 후 KDC 발전에 일조하기 위한 것이다. 고찰대상으로는 기본적인 장치임에도 불구하고 제외된 것들(내부보조표, 우선순위표, 해설, 신 구대비표 등)을 비롯하여 본표, 조기표(공통보조표), 주기, 색인, 양자택일 등을 분석대상으로 삼았으며, 나아가 오류, 표기부적절, 누락, 표현일관성결여 및 삭제해야 할 부분 등도 바로 잡고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.222-225
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• 2002

The nitrogen oxides, NO and NO2, abbreviated usually as NOx, emitted from combustion facilities such as power plants and automobiles are the typical air-pollutants causing acid rain and photochemical smog. In order to solve the NOx-related pollution problems effectively, we need efficient techniques to monitor NOx in the combustion exhausts and in environments. Development of solid-state electrochemical devices for detecting NOx is demonstrated based on various combination of solid electrolytes and auxiliary sensing materials. The object of this research is to develop various sensor performance for solid state amperometric sensor, and to test gas sensor performance manufactured. So we try to present a guidance for developing amperometric gas sensor.