• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.174-176
• /
• 2008

HYOSUNG manufactured and tested 1kw class PEFC systems to generate electrical and thermal energy for each residential usage. In particular, HYOSUNG developed Power conditioning system that performs about 91% electrical conversion ratio specified in 1kW class PEFC systems. Prior to system integration, we tested each performances of components to derive control issues from it. In addition, we have been developing the adequate simulator to describe and predict system performance. In this paper, we verified HYOSUNG's 1kW class PEFC systems are valid for residential energy sureces by testing the characteristics of systems and performances of main component.

• Journal of Electrical Engineering and Technology
• /
• 제13권1호
• /
• pp.250-255
• /
• 2018

This paper presents a method for minimizing standby power consumption in wireless power transfer (WPT) system via magnetic resonance coupling (MRC) that operates at 6.78 MHz. The proposed circuit controls the required capacitance according to operational condition in order to reduce standby power consumption. Based on an impedance characteristic of the class-E power amplifier, operational principles of the proposed circuit are analyzed. Moreover, to verify the effectiveness of the proposed class-E power amplifier, an 8 W prototype for WPT system is implemented. The measured input power of the proposed class-E power amplifier at standby condition is reduced from 5.81 W to 3.53 W.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집D
• /
• pp.744-750
• /
• 2001

In now a days, the concern to environment and energy saving problem is increased worldly. So many countries are developing the wind power system as clean energy system. In our country, Cheju local government has the plan of the Cheju Island wind farm and 600kW class 2 wind turbines, 660kW class 2 turbines, 225kW class 1 turbine and 750kW class 2 turbines has been operated at Hangwon. In this paper the field operation data of the wind turbines was analyzed and was compared with the characteristics & performance of each turbines. As the results, we would find the possibility of wind turbine in domestic and suggest the direction of developing technology.

• 대한수학회지
• /
• 제55권3호
• /
• pp.671-694
• /
• 2018

In this paper, we investigate the weighted vector-valued bounds for a class of multilinear singular integral operators, and its commutators, from $L^{p_1}(l^{q_1};\;{\mathbb{R}}^n,\;w_1){\times}{\cdots}{\times}L^{p_m}(l^{q_m};\;{\mathbb{R}}^n,\;w_m)$ to $L^p(l^q;\;{\mathbb{R}}^n,\;{\nu}_{\vec{w}})$, with $p_1,{\cdots},p_m$, $q_1,{\cdots},q_m{\in}(1,\;{\infty})$, $1/p=1/p_1+{\cdots}+1/p_m$, $1/q=1/q_1+{\cdots}+1/q_m$ and ${\vec{w}}=(w_1,{\cdots},w_m)$ a multiple $A_{\vec{P}}$ weights. Our argument also leads to the weighted weak type endpoint estimates for the commutators. As applications, we obtain some new weighted estimates for the $Calder{\acute{o}}n$ commutator.

• 한국유체기계학회 논문집
• /
• 제15권3호
• /
• pp.5-11
• /
• 2012

This study is to develop a 1kW-class horizontal axis wind turbine(HAWT) rotor blade which will be applicable to relatively low wind speed regions in southwest islands in Korea. Shape design of 1kW-class small wind turbine rotor blade is carried out using a blade profile with relatively high lift to drag ratio by blade element momentum theory(BEMT). Aerodynamic analysis on the newly designed rotor blade is performed with the variation of tip speed ratio. Power coefficient and pressure coefficient of the designed rotor blade are investigated according to tip speed ratio.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
• /
• pp.60.2-60.2
• /
• 2011

This study is to develop a 1kW-class small wind turbine blade which will be applicable to relatively low speed regions. For this blade, a high efficiency wind turbine blade is designed and a light and low cost composite structure blade is adopted considering fatigue life. In this study, shape design of 1kW-class small wind turbine blade for hybrid power generation system is carried out by BEMT(blade element momentum theory). X-FOIL open software was used to acquire lift and drag coefficients of the 2D airfoils used in power prediction procedure. Moreover, pressure and velocity distributions are investigated according to TSR by CFD analysis.

• Journal of electromagnetic engineering and science
• /
• 제16권1호
• /
• pp.52-56
• /
• 2016

This paper suggests a class-F power amplifier with split open-end stubs to provide a broadband high-efficiency operation. These stubs are designed to have wide bandwidth by splitting wide open-end stubs into narrower stubs connected in shunt in an output matching network for class-F operation. In contrast to conventional wideband class-F designs, which theoretically need a large number of matching lines, this method requires fewer transmission lines, resulting in a compact circuit implementation. In addition, the open-end stubs are designed with slant ends to achieve additional wide bandwidth. To verify the suggested design, a 10-W class-F power amplifier operating at 1.7 GHz was implemented using a commercial GaN transistor. The measurement results showed a peak drain efficiency of 82.1% and 750 MHz of bandwidth for an efficiency higher than 63%. Additionally, the maximum output power was 14.45 W at 1.7 GHz.

• 한국전자파학회논문지
• /
• 제26권3호
• /
• pp.248-256
• /
• 2015

본 논문에서는 4G 이동 통신을 위한 메탈 폰용 보조 슬롯 하이브리드 MIMO 안테나를 설계하고, 이를 제작하였다. 보조 슬롯은 단말기 후면 메탈 커버에 슬롯을 내어 LTE class 40 대역을 담당하게 하였다. 보조 슬롯은 모노폴 안테나와 함께 하이브리드로 동작한다. 제안 안테나는 LTE class 13/ LTE class 14/ CDMA/ GSM/ DCS/ PCS/ W-CDMA/ LTE class 40 대역에서 VSWR 3:1 이하의 조건을 만족하였다. MIMO 동작을 위한 ECC(Envelope Correlation Coefficient)는 전 대역에서 0.2 이하의 특성을 보였다. MTG 무반사실 측정한 안테나의 평균 이득은 -5.57~-1.45 dBi이고, 효율은 27.75~71.6%로 측정되었다.

• 한국전자파학회논문지
• /
• 제27권4호
• /
• pp.395-398
• /
• 2016

본 논문에서는 이동 통신 메탈 폰 단말기용 보조 문자슬롯 하이브리드 MIMO 안테나를 설계하고, 이를 제작하였다. 보조 문자슬롯은 단말기 후면 메탈 커버에 슬롯을 내어 LTE class 40대역을 담당하게 하였다. 문자 슬롯으로 2종류의 문자를 설계하였으며, 주 안테나인 모노폴+IFA 하이브리드와 함께 동작하도록 하였다. 안테나는 LTE class 13 / LTE class 14 / CDMA / GSM / DCS / PCS / W-CDMA / LTE class 40 대역에서 VSWR 3: 1 이하의 조건을 만족하였다. 무반사실에서 측정한 안테나의 평균이득은 전체 대역에서 -5.57~-1.45 dBi이고, 효율은 27.75~71.6 %로 측정되었다.

• 한국가스학회지
• /
• 제19권4호
• /
• pp.41-48
• /
• 2015

스크롤 팽창기의 성능특성은 유기랭킨사이클 (ORC) 시스템의 성능에 가장 중요한 변수이다. 본 연구에서는 1kW급 ORC 시스템을 구성하여 다양한 작동 조건에서 스크롤 팽창기의 성능특성을 파악하였다. ORC 시스템은 증발기, 스크롤 팽창기, 응축기, 작동유체펌프로 구성되어 있으며, 작동유체로 R245fa를 사용하였다. 고온수 온도는 50kW급 전기히터에 의해 $80^{\circ}C$에서 $115^{\circ}C$까지 제어되었다. 스크롤 팽창기의 최대 등엔트로피 효율은 77%로 측정되었고, ORC 시스템의 축동력은 열원의 온도 조건 및 팽창기의 회전속도에 따라 0.5kW에서 1.8kW까지 측정되었다.