• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권2호
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• pp.86-91
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• 1999

In order to analyse the degradation process of epoxy/glass fiber for outdoor condition, FRP laminate was exposed to the wavelength of ultraviolet rays and evaluated by comparing contact angle, surface resistivity, surface potential decay, and ESCA spectrum respectively. As irradiation energy are increased, the surface properties were steeply decreased in the range of 300[nm]. But the measured values within the scope of400[nm]∼440[nm] showed a increase as compared with the untreated ones. Also, fromthe result of ESCA spectrum, it was confirmed plenty of oxygen groups on the spot showing the maximum decrease of surface properties and the existence of ether groups on the surface of coloring phase. We can conclude that the degradation phenomena on the surface of epoxy composites are dominated by the induction of ester and carboxyl groups.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권2호
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• pp.181-188
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• 2005

In this paper, a DC smoothing filterless soft switching pulse modulated high frequency AC power conversion circuit connected to utility. frequency AC power source is proposed for consumer induction heating hot water producer, steamer and super heated steamer. The operating principle of DC link filterless utility frequency AC-high frequency AC (HF AC) power conversion circuit defined as high frequency cycloinverter is described, which can operate under a principle of ZVS/AVT and power regulation based on alternate asymmetrical PWM in synchronization with the utility frequency single phase AC positive or negative half wave voltage. The dual mode modulation control scheme based on high frequency PWM and commercial frequency AC voltage PDM for the proposed high frequency cycloinverter are discussed to enlarge its soft switching commutation operating range for wide HF AC power regulation. This high frequency cycloinverter is developed for high frequency IH Dual Packs Heater (DPH) type boiler used in consumer and industrial fluid pipeline systems. Based on the experiment and simulation results, this high frequency cycloinverter is proved to be suitable for the consumer use IH-DPH boiler and hot water producers. The cycloinverter power regulation and power conversion efficiency characteristics are evaluated and discussed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.247-250
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• 2001

This paper presents a simple and cost effective circuit topology of single-ended type high frequency quasi-resonant PWM inverter using IGBTs, which can operate under wide soft switching operation range based on ZCS for main power switch as compared with a conventional active voltage-clamped ZVS-PWM high frequency quasi-resonant inverter developed previously. In principle, this new circuit topology can efficiently operate under a constant frequency PWM control-based power regulation scheme. In particular, it is noted that the zero current soft switching (ZCS) commutation can achieve for the main active power switch. On the other hand, the zero voltage soft switching (ZVS) commutation can also achieve for the auxiliary active power switch. The operating principle of this high-frequency Inverter treated here and its power regulation characteristics are illustrated on the basis of the simulation and feasible experimental results.

• 한국항행학회논문지
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• 제24권2호
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• pp.101-106
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• 2020

유도전동기의 속도 제어를 원활하게 수행하기 위해서는 필요한 회전자 속도 정보를 얻어야 한다. 속도 정보를 얻으려면 센서를 사용하여 얻어야 하지만, 센서를 사용하지 않고 적절한 알고리즘을 이용하여 얻을 수도 있다. 속도 정보를 얻기 위해서 모델 기준 적응 시스템(MARS; model reference adaptive system)을 사용하여 시스템을 설계 하였고, 유도전동기의 속도 제어 방식 중에 하나인 간접 벡터 제어 방식으로 전동기의 전류와 회전자 파라미터 값으로부터 연산된 슬립 주파수를 회전자 속도와 합하여 자속의 위치 정보를 얻어내는 방식을 사용하였다. 실제 자속 정보 없이도 넓은 속도 영역에서 간단하게 순시 전류 제어를 행할 수 있으며 제어기의 구조가 간단하다는 장점을 가질 수 있다. 따라서 본 논문에서는 간접 벡터 제어 방식을 기반으로 제어 시스템을 구성하였고, 이를 실현하기 위해 필요한 회전자 속도 정보를 센서로 사용하지 않고 개발한 지능형 알고리즘으로 추정하여 유도전동기의 속도 제어 시스템을 개발하였다.

• 전기학회논문지
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• 제65권3호
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• pp.411-418
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• 2016

In accordance with global energy conservation policies such as MEPS(Minimum Energy Performance Standard), electric motor industry is moving to super-high-efficiency machines and research to develop IE4 (International Energy Efficiency Class4) motors has been launched. In this situation, SynRM (Synchronous Reluctance Motor) has been attracting attention in place of induction motor which hardly provides super premium efficiency. As a result, much research on SynRM is being performed at home and abroad. Also, some products have already been appearing in the market. Compared to induction motor, SynRM has better efficiency per unit area and wider operating range. Although the utilization of control system in synchronous motor results in higher prices, we still need to concentrate on developments of SynRM so as to comply with the new policies. This study demonstrated the electromagnetic design methods of super-premium SynRM while maintaining the frame of existing IE3 induction motor for blower. We documented the design procedures for generating high saliency which is the most essential and mechanical stress analysis is also treated. In conclusion, we proved the validity of our design by manufacturing and testing our SynRM models.

• 지구물리와물리탐사
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• 제7권2호
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• pp.136-147
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• 2004

본 논문에서는 자기지전류 탐사법에 대한 3차원 이상체의 모형 반응 결과를 분석하였다. 분석에 이용된 3차원 모형은 비전도성 배경 매질 내에 전도성 고립이상체가 존재하는 모형과, 같은 모형에 전도성 표토층을 추가한 모형이다. 지하의 전도성 이상체에 의한 겉보기 전기비저항 이상에는 뚜렷한 주파수 의존성이 존재하며, 이는 이상체 주변에 발생되는 전류 집중 및 유도 전류 거동의 주파수 의존성 때문이다. 지표에서 tipper와 induction vector의 반응에도 뚜렷한 주파수 의존성이 존재하였으며, 그 외에도 tipper와 induction vector의 반응은 이상체의 위치와 직접적인 연관성이 존재하였다. 또한, 2차원 탐사를 가정하여 한 측선에서 겉보기 전기비저항과 위상, induction vector를 분석하면, 3차원 이상체의 존재 여부 및 위치 파악에 도움을 줄 것으로 판단되었다. 전도성 표토층을 추가한 모형의 반응은 대체적으로 고립이상체 모형의 반응과 비슷한 양상을 나타내었지만, 전도성 표토층의 영향으로 이상체에 의한 반응의 크기가 감소하였으며, 이상체의 영향이 나타나는 영역도 크게 감소하였다. 위와 같이 본 연구에서 논의된 3차원 모형 반응에 대한 분석 결과 및 그 방법은 지하 구조의 3차원 반응의 이해와 MT 탐사 자료의 해석에 효과적인 지침이 될 것으로 생각된다.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.166-170
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• 2014

In this paper, we investigate the electric and magnetic properties of the engine oil, and estimate its changing time in transport truck. The four diesel trucks are selected, and the capacitance and inductance are investigated with parallel capacitor and induction coil, respectively. The measured capacitance gradually increases up to 10,000~14,000 km due to the activation of antioxidant, and then decreasing phenomena happen. The inductance decreases and the saturation began in 10,000~14,000 km range. Although the behavior of inductance is different from that of capacitance, but changing points are similar. From those results, we can estimate the changing time of engine oil is around 10,000~14,000 km and the inductance can be used for monitoring of engine oil in transport trucks.

• 한국인터넷방송통신학회논문지
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• 제21권2호
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• pp.131-136
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• 2021

직류 전동기 (DC Motor)는 유도전동기와 더불어 광범위한 영역에서 사용되고 있는 중요한 구동원이다. 비록 구조가 복잡하고 유지보수의 측면에서 불리한 점이 있어 오늘날 산업의 동력원으로서 대부분의 수요를 유도전동기에 내어준 상태이지만 우수한 제어성능으로 인하여 소형의 제어용 전동기로는 직류 전동기가 꾸준하게 사용되는 중이다. 또한 계자에 영구자석을 쓸 수 있는 구조로 자석재료의 발달과 더불어 고출력, 고효율 운전이 가능한 구조의 직류 전동기가 개발되고 있다. 그리고 인버터를 이용한 유도전동기의 경우보다 제어기의 구성이 단순하여 아직도 직류 전동기를 선호하는 수요도 무시할 수 없을 정도여서 여전히 중요한 동력원으로 자리를 차지하고 있는 전동기이다. 이러한 경향을 고려하여 본 논문에서는 시뮬레이션을 통한 모델링, EPLD를 이용한 PWM 발생회로 및 전동기구동회로, 프로세서 이용한 PI 제어 등의 하드웨어 구현을 통한 직류전동기의 제어성능을 살펴보고자 한다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.459-465
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• 2017

This paper describes a performance analysis of self-excited eddy current brake(SECB). Stator winding of SECB is connected by capacitor instead of voltage source, and SECB's braking force is generated by L-C resonance. SECB has wide range of driving and nonlinear inductance as well. Therefore, it is important to select capacitance based on the value of inductance. This paper discusses about the process of deciding capacitance and the change of resonance frequency based on the inductance change in each speed. Also the braking force was confirmed by the experimental model of SECB.

• 한국IT서비스학회지
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• 제19권3호
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• pp.89-100
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• 2020

The wireless power transmission market is growing at an average annual rate of 51.5% from $ 16.4 billion in 2015 to $ 131.1 billion in 2020. However, there are limitations to commercialization due to the development of standards and technologies. Thus, this study identified trends in standards and regulations by market and by country. The research collected and filtered a total of 69,488 worldwide wireless power transfer patents by June 2019 and extracted a total of 28,555 patents. Based on this, technology development status was analyzed and predicted. In this study, long-distance and short-range technology development with high technology development difficulty and low technology development ratio could lead to growth of the entire wireless charging market. It is analyzed that investment and policy preparation are necessary to secure source technology for long-distance / near technology development than China, Japan and Europe.