• Journal of the Korean Solar Energy Society
• /
• v.21 no.1
• /
• pp.43-49
• /
• 2001

Informations of the solar radiation component are essential for modeling various solar energy systems. These Informations are particularly used for middle and high temperature applications, those need concentrating direct normal insolation. In order to estimate the performance of concentrating systems, it is necessary to know the intensity of the beam radiation, as only this component can be concentrated. The Korea Institute of Energy Research(KIER) has began collecting solar radiation component data since August, 1996. KIER's component data will be extensively used by concentrating system users or designers as well as by research institutes.

• Solar Energy
• /
• v.12 no.2
• /
• pp.28-42
• /
• 1992

This investigation is carried out numerically for the two dimensional natural convection and surface radiation heat transfer in a square enclosure. The bottom wall is a constant heat flux at hot temperature and also top wall is isothermal at cold temperature whereas the left and right side walls are adiabatic except a transparent window on the right side partially. The exchange of radiant energy is obtained by the net radiation method and the shape factor by the crossed string method. The change in temperature and Nusselt number distributions of the walls due to the effect of the wall emissivity for various emissivities and for various dimensionless insolation energies are investigated. The dimensionless local convective heat flux and local radiative heat flux distributions in the wall except an adiabatic wall are also compared.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.50-55
• /
• 2009

Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. For the validation, estimated solar radiation fluxes are compared with observed solar radiation fluxes at 16 sites over the Korean peninsular from January 1982 to December 2007. Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.58 to +3.8% from the measured values and the yearly averaged horizontal global insolation of Korean peninsula was turned out to be $3.59kW/m^2/day$.

• Proceedings of the KIEE Conference
• /
• 2001.10a
• /
• pp.328-330
• /
• 2001

The construct of photovoltaic module array, main power source of photovoltaic system, is very important to the efficiency improvement of whole photovoltaic system. Photovoltaic modules are usually connected in series or parallel to meet power capacity required. Since output characteristics of a photovoltaic module are greatly fluctuated on the variation of insolation, temperature and its type, the maximum open circuit voltage and output operating voltage of photovoltaic module array must exist in the admissible input voltage range of inverter system under any operating conditions. In this paper, we present the selection and array method of photovoltaic modules through simulation for the coupling loss reduction between photovoltaic modules and a inverter.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.10
• /
• pp.1968-1975
• /
• 2009

The paper proposes a novel control algorithm for tracking maximum power of PV generation system.. The maximum power of PV array is determinated by a insolation and temperature. Prior considered the term in PV generation system is how maximum power point(MPP) is accurately tracked.. The paper proposes a fuzzy neural network(FNN) control algorithm so as to accurately track those maximum power points. The proposed control algorithm comprises the antecedence part of fuzzy rule and clustering method, multi-layer neural network in the consequent part. FNN has the advantages which are depicted both high performance and robustness in fuzzy control and high adaptive control in neural network.. Specially, it can show the outstanding control performance for parameter variations appling to non-linear character of PV array. In this paper, the tracking speed and the accuracy prove the validity through comparing a proposed algorithm with a conventional one.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.25 no.1
• /
• pp.29-36
• /
• 2020

In this study, a variable step algorithm is proposed on the basis of the perturb and observe method. The proposed algorithm can follow the maximum power point (MPP) quickly when solar irradiance changes rapidly. The proposed technique uses the voltage change characteristic at the MPP when the environment changes because of insolation or temperature. The MPP is tracked through the voltage control using a variable step method. This method determines the sudden change of solar irradiance by setting the threshold value and operates in fast tracking mode to track the MPP rapidly. When the operation point reaches the MPP, the mode switches to the variable step mode to minimize the steady state error. In addition, the output disturbance is decreased through the optimization of the control method design. The performance of the proposed MPPT algorithm is verified through simulation and experiment.

• Proceedings of the KIEE Conference
• /
• 2005.11c
• /
• pp.103-106
• /
• 2005

A lot of R&D on the diagnosis of stator winding insolation for large rotating machines has been carried out since the 1970s. The on-line partial discharge measurement has proved to be an effective technique in the evaluation of the state of stator insulation in high voltage rotating machines. The purpose of this paper is to describe the method of the on-line partial discharge measurement on stator windings for hydro- generator with ceramic sensor and measuring system. We developed ceramic coupling sensor, partial discharge measuring system, terminal box and index parameters.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.1374-1376
• /
• 2003

The output of solar cell or array depends on the weather conditions such as cell temperature and insolation level. If the output of the photovoltaic system would be regularly generated under any weather conditions, it is so easy to develop the inverter, its related system, and also control algorithm. This can be performed by the VISC(virtual-implemented solar cell) system studied in this paper. And a few I-V curves are provided by the manufacturers, and so any I-V value between the given curves is unknown. The new model for solar cell is proposed which is based on the interpolation. Both simulation and experiment are executed to show the validity of the proposed VISC system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.05a
• /
• pp.412-415
• /
• 2009

This paper analyzes efficiency of photovoltaic(PV) tracking system using position solar algorithm(PSA). Solar location tracking system is needed for efficiently and intensively using PV system independent of environmental condition. PV tracking system of program method is presented a high tracking accuracy without the wrong operating in rapidly changed insolation by the clouds and atmospheric condition. Therefore, this paper analyzes efficiency of PV system using PSA algorithm for more correct position tracking of solar. Also, controlled altitude angle and azimuth angle by applied algorithm is compared with data of korea astronomy observatory. And this paper analyzes the tracking error and roves the validity of applied algorithm.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.343-344
• /
• 2012

In high power PV generation system, the solar cell normally generates wide output voltage depending on the insolation, cell's temperature and shade effect. This paper will propose a high efficiency converter allowing the wide input voltage to supply stable voltage with the controller and operation for the PV generation system. The proposed converter consists of two stages comprising SEPIC with a coupled inductor and LLC, which generates 24 V of output at the final output terminal. In this paper, a design method and experimental results with a test-bed of 50 W will be presented to validate the proposed converter.