• 에너지공학
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• 제25권4호
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• pp.62-73
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• 2016

자연채광 시스템은 자연광의 건물 실내 유입을 통한 실내조명에 상당히 효율적으로 적용될 수 있다. 특히, 건물에서 사용되는 에너지 중 28%는 조명에너지에 사용되는 점을 감안하면, 인공조명에의 의존도를 낮출 수 있는 자연채광시스템의 역할은 상당히 중요하다고 할 수 있다. 본 연구에서는 최근 국내에 보급된 다양한 추적식 자연채광시스템(Active Daylighting System)의 특성 및 이용 현황에 대한 조사와 분석을 수행하였다.

• 전력전자학회논문지
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• 제26권1호
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• pp.38-45
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• 2021

The photovoltaic module has the characteristic of changing its output characteristics depending on the amount of radiation and temperature, where the arrays that connect them in series and parallel also have the same characteristics. These characteristics require the MPPT technique to find the maximum power point. Existing P&O and IncCond cannot find the global maximum power point (GMPP) for partial shading. Moreover, in the case of Improved-GMPPT and Enhanced Search-Skip-Judge-GMPPT, GMPP due to partial shading can be found, but the variation in the open voltage during temperature fluctuations will affect the operation of the Skip and will not be able to perform accurate MPPT operation. In this study, we analyzed the correlation between voltage, current, and power under solar module and array conditions. We also proposed a technique to find the maximum power point even for temperature fluctuations using not only the amount of radiation but also the temperature coefficient. The proposed control technique was verified through simulations and experiments by constructing a 2.5 kW single-phase solar power generation system.

• 한국전자통신학회논문지
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• 제9권2호
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• pp.231-242
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• 2014

지구 온난화로 인한 급격한 기후 변화로 인해 단위 면적당 작물의 생산성 향상 및 고품질 작물 재배에 관심이 고조되고 있다. 따라서 본 논문에서는 기존의 담액 수경방식이나 인공광원을 이용한 수경재배 방식이 아닌 광원 트래킹 기법을 적용한 양액 순환 방식의 수경재배기 제어 관리 시스템을 제안한다. 제안하는 수경재배기는 일정한 양의 양액과 물을 수로로 흘려보내 순환시키는 형태인 양액 순환 방식과 수경재배기 하단 부분의 작물도 지속적인 광합성 작용이 가능 하도록 피라미드 형태의 다단구조식으로 설계한다. 아울러 광원 트래킹 기법은 기존 2축, 4축 센서 방식이 아닌 태양광의 그림자를 추적하기 위한 중심축 센서 방식의 5축 센서 방식으로 설계한다. 본 논문에서 제안한 수경재배기를 통해 기존 연구에서 소개되지 않은 광원 트래킹 기법은 작물에 지속적인 광합성 작용으로 작물의 생장 속도를 단축시킬 수 있었으며, 피라미드형태의 다단식구조로 상, 하단 구분 없이 모든 작물이 동일한 형태의 생육환경을 제공받을 수 있어 단위 면적당 높은 작물 생산량이 예상된다.

• 태양에너지
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• 제18권3호
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• pp.25-30
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• 1998

PTC용 태양추적장치는 최대 집열을 위하여 PTC를 항상 태양광이 입사되는 방향으로 일치시키기 위한 자동제어시스템이다. 본 연구는 마이크로프로세서를 사용하는 PTC용 1축 태양추적장치의 개발에 관한 것이다. 개발된 태양추적장치는 태양 위치를 판별하는 태양 센서와 DC 모터 위치제어기로 구성되어 있으며, 80c196KC를 사용하는 제어장치는 아날로그 입력 장치, 24V DC 서보모터제어기, 디지털 I/O로 구성되어 있다. 태양센서는 photodiode를 사용하여 제작되었으며, 태양센서의 법선 방향으로부터 ${\pm}50^{\circ}$ 이내에 위치하는 태양을 감지할 수 있도록 설계되었다. 본 연구에서 개발된 태양추적장치는 현재 한국에너지기술연구소에 설치되어 있는 PTC에서 사용되고 있으며, 태양추적 정확도에 관한 연구가 현재 진행되고 있다.

• 한국태양에너지학회 논문집
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• 제37권6호
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• pp.69-77
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• 2017

The amount of solar irradiation obtained by a photovoltaic (PV) solar panel is the major factor determining the power generated by a PV system, and the array tilt angle is critical for maximizing panel radiation acquisition. There are three types of PV systems based on the manner of setting the array tilt angle: fixed, semi-fixed, and tracking systems. A fixed system cannot respond to seasonal solar altitude angle changes, and therefore cannot absorb the maximum available solar radiation. The tracking system continually adjusts the tilt angle to absorb the maximum available radiation, but requires additional cost for equipment, installation, operation, and maintenance. The semi-fixed system is only adjusted periodically (usually seasonally) to obtain more energy than a fixed system at an overall cost that is less than a tracking system. To maximize semi-fixed system efficiency, determining the optimal tilt angle adjustment schedule are required. In this research, we conducted a simulation to derive an optimal operation schedule for a semi-fixed system in Seoul, Korea (latitude $37.5^{\circ}$). We implemented a solar radiation acquisition model and PV genereation model on MATLAB. The optimal operation schedule was derived by changing the number of tilt angle adjustments throughout a year using a Dynamic Algorithm. The results show that adjusting the tilt angle 4 times a year was the most appropriate. and then, generation amount of PV system increased 2.80% compared with the fixed system. This corresponds to 99% compared to daily adjustment model. This increase would be quite valid as the PV system installation area increased.

• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.118-124
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• 2010

In order to develop commercial model of 10kW dish-Stirling solar thermal power system, modification for the exiting facility was taken for a year as a Leading Project in KIER. During the project, solar tracking system, control and monitoring system and high durability reflector were developed and long term operation were performed. The solar tracking system was tested for four months to investigate the degree of precision and adapted to the control system for an actual operation from October in 2009. The sun tracking accuracy of ${\pm}4$ mrad using modified control system was obtained and the system operated successfully during the experimental period. The monitoring system displays engine pressure, electric generation amounts, generator RPM, receiver temperatures, and etc. from Stirling engine and weather data of Direct Normal Irradiation, Horizontal Global Insolation, wind speed & direction, and atmosphere temperature from weather station. According to the operating results in a clear sky day, electric power of 6,890 W was generated at the DNI value of 850 W/$m^2$ and the averaged solar-to-electricity efficiency during a whole day reached to 18.99%. From the overall operating results, linear power generation trend could be observed with increasing DNI value. The solar-to-electricity efficiency achieved to 19% around the DNI value of 700 W/$m^2$ and increased to 20% when the DNI value goes up to 900 W/$m^2$.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.571-575
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• 2002

Generation of electrical energy faces many problems today. Solar power converters were used to convert the electrical energy from the solar arrays to a stable and reliable power source. The object of this paper is to analyze and design DC-DC converters in a solar energy system to investigate the performance of the converters. A DC-DC converter can be commonly used to control the power flow from solar cell to load and to achieve maximum power point tracking(MPPT), DC-AC converter can also be used to modulate the DC power to AC power being applied on common utility load. A DC-DC converter is used to boost the solar cell voltage to constant 360(V) DC link and to ensure operation at the maximum power point tracking, If a wide input voltage range has to be covered a boost converter is required. In this paper, author described that simulation and experimental results of PV system contain solar modules, a DC-DC converter(boost type chopper), a DC-AC converter (3-phase inverter) and resistive loads.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.359-361
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• 2010

This research is thing about location choice of solar power generation equipment to increase efficiency of solar power generation equipment. In the case of current solar power generation equipment, location of large scale solar power generation equipment facilities choice or, have localized in small scale equipment by individual. This research uses various climatic elements of small scale area for efficient location choice of solar power generation facilities and quantity of solar radiation did back-tracking.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권4호
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• pp.472-480
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• 2014

The In solar power system, the height and azimuth of the sun are important parameters which control generated power magnitude. The tracking method that controls the daily generation magnitude according to latitude and longitude using the two axles is often used in the existing sunlight tracking system today. In this two-axle PV track control system, the self-load is concentrated on one FRAME. It is influenced of the regular load, snow load and the wind load, etc. It is difficult to set up the system in the conventional building. This research is a development about the small-scale economy track device of independent load-dispersing solar generation system. The position tracking algorithm is through new coordinates transformation calculating the height and azimuth of the sun.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.617-621
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• 2001

This paper presents a maximum power point tracking algorithm for Photovoltaic array using only instantaneous output current information. The conventional Hill climbing method of peak power tracking has a disadvantage of oscillations about the maximum power point. To overcome this problem, we have developed a algorithm, that will estimate the duty ratio corresponding to maximum power operation of solar cell. The estimation of the optimal duty ratio involves, finding the duty ratio at which integral value of output current is maximum. For the estimation, we have used the well know Lagrange's interpolation method. This method can track maximum power point quickly even for changing solar insolations and avoids oscillations after reaching the maximum power point.