• 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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• 제22권3호
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• pp.11-20
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• 2002

This paper proposed a MPPT(Maximum Power Point Tracking) control algorithm for PV(Photovoltaic) array based on a modified constant voltage control MPPT algorithm at low insolation. This method which combined a reference voltage control and a constant voltage control algorithm. In contrast to the typical conventional MPPT algorithm, the proposed method have been obtained high efficiency and good performance in all insolation intensity. The proposed algorithm is verified through simulation and experiment.

• 전력전자학회논문지
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• 제16권5호
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• pp.521-531
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• 2011

본 논문은 그림자 영향을 고려한 PV(Photovoltaic) 시스템의 VPO(Variable Perturbation & Observation)MPPT(Maximum Power Point Tracking) 제어를 제시한다. 태양전지의 출력 특성은 비선형이고 온도, 일사량 및 그림자의 영향을 많이 받는다. MPPT 제어는 태양광발전 시스템의 출력 및 효율을 증가시키기 위한 매우 중요한 기술이다. 종래의 PO(Perturbation & Observation)와 IC(Incremental conductance) 등은 지속적인 자려진동에 의해 MPP(Maximum Power Point)를 찾는 방법으로 그림자 영향에 의해 출력이 급격하게 변할 경우 MPPT 제어를 수행하지 못한다. 이러한 문제점을 해결하기 위해 출력 변동에 따라 스텝 값이 변하는 새로운 제어 알고리즘을 제시한다. 제시한 알고리즘은 일사량, 온도 및 그림자 영향에 대해 종래의 제어 알고리즘과 응답특성을 비교하고 이를 통해 제시한 알고리즘의 타당성을 입증한다.

• 통합자연과학논문집
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• 제15권3호
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• pp.99-110
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• 2022

Solar photovoltaic (PV) system shows a non-linear current (I) -voltage (V) characteristics, which depends on the surrounding environment factors, such as irradiance, temperature, and the wind. Solar PV system, with current (I) - voltage (V) and power (P) - Voltage (V) characteristics, specifies a unique operating point at where the possible maximum power point (MPP) is delivered. At the MPP, the PV array operates at maximum power efficiency. In order to continuously harvest maximum power at any point of time from solar PV modules, a good MPPT algorithms need to be employed. Currently, due to its simplicity and easy implementation, Perturb and Observe (P&O) algorithms are the most commonly used MPPT control method in the PV systems but it has a drawback at suddenly varying environment situations, due to constant step size. In this paper, to overcome the difficulties of the fast changing environment and suddenly changing the power of PV array due to constant step size in the P&O algorithm, least mean Square (LMS) methods is proposed together with P&O MPPT algorithm which is superior to traditional P&O MPPT. PV output power is predicted using LMS method to improve the tracking speed and deduce the possibility of misjudgment of increasing and decreasing the PV output. Simulation results shows that the proposed MPPT technique can track the MPP accurately as well as its dynamic response is very fast in response to the change of environmental parameters in comparison with the conventional P&O MPPT algorithm, and improves system performance.

• 전력전자학회논문지
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• 제18권6호
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• pp.507-514
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• 2013

In this paper, the proposed charging algorithm is converted from the charging mode to compensate the transient state in the solar battery charging system. The maximum power point tracking (MPPT) control methods and the various charging algorithms for the optimal battery charging are reviewed. The proposed algorithm has excellent transient characteristics compare to the previous algorithm by adding the optimal control method to compensate the transient state when the charging mode switches from the constant current mode to the constant voltage mode based on the conventional constant-current constant-voltage (CC-CV) charging algorithm. The effectiveness of the proposed method has been verified by simulations and experimental results.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.107-110
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• 2009

The photovoltaic power system is effected by atmospheric condition. Therefore, The maximum power point tracking(MPPT) algorithm of the Photovoltaic (PV) power system is needed for high efficiency. Many MPPT techniques have been considered in past, but In this paper, the author analyzes widely known P&O MPPT algorithm and ImP&O algorithm, and presents new MPPT algorithm complementing weaknesses of other two algorithms.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.136-137
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• 2017

Maximum power point tracking (MPPT) under partial shading condition (PSC) is a challenging process in the PV array system. The shaded PV panel makes different peak patterns on the P-V curve and misguides the MPPT algorithm. Various kinds of global MPP (GMPP) detecting algorithms are used to overcome this issue. Generally, too frequent execution of GMPP tracking algorithm reduces the achievable power of PV panel due to time spent on the scanning process. Thus, partial shading detection algorithm is essential for efficient utilization of solar energy source. While conventional method only detects fast shading patterns, the proposed algorithm always shows superb performance regardless of the speed of partial shading patterns.

• 천문학논총
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• 제30권3호
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• pp.811-819
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• 2015

The e-CALLISTO is a network of CALLISTO (Compact Astronomical Low-frequency, Low-cost Instrument for Spectroscopy in Transportable Observatories) spectrometers which detect solar radio bursts 24 hours a day in frequency range 45-870 MHz. The number of channels per spectrum is 200 and the time resolution of whole spectrum is 0.25 second. The Korean e-CALLISTO station was developed by Korea Astronomy and Space Science Institute (KASI) collaborating with Swiss Federal Institute of Technology Zurich (ETH Zurich) since 2007. In this paper, we report replacement of the tracking mount and development of the control program using Visual C++/MFC. The program can make the tracking mount track the Sun and schedule CALLISTO to start and to finish its observation automatically using the Solar Position Algorithm (SPA). Daily tracking errors (RMSE) are 0.0028 degree in azimuthal axis and 0.0019 degree in elevational axis between 2014 January and 2015 July. We expect that the program can save time and labor to make the observations of solar activity for space weather monitoring, and improve CALLISTO data quality due to the stable and precise tracking methods.

• 반도체디스플레이기술학회지
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• 제13권4호
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• pp.43-48
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• 2014

Two-level inverter has some disadvantages like high harmonics contained in the output current, efficiency limit and stress to switching device as IGBT and FET. Many researches have reported multi-level inverter to complement two-level inverter of problems. In this paper, we suggest MPPT algorithm of multi-string three-level solar inverter that considered nowadays. We added midpoint controller in order to implement the MPPT algorithm because the three-level inverter has to need midpoint controller and procured the stability of direct current link. We verify the superiority of multi-string T-Type inverter and the algorithm we suggested with solar irradiance variation experiment and MPPT efficiency measurement. The MPPT efficiency was confirmed with a high efficiency more than 99.97%.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.255-258
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• 2004

The SAR(Solar Array Regulator) of KOMPSAT(Korea Multi Purpose SATellite)-1, 2 regulates a photovoltaic power according to the duty ratio commands of the ECU. But the ECU has so many other jobs that it can not calculate the solar array condition immediately. It means the SAR cannot always generate the maximum power of a photovoltaic. Nowadays, the commercial photovoltaic systems are using a controller operated by digital processing. But the usage for satellite is not adaptable. It is not easy to find the processor of the space grade and the price is expensive. So in this paper, the simple analog MPPT(Maximum Power Point Tracking) algorithm is proposed for the small satellite in LEO. This algorithm does not need any calculation of power by multiplication of voltage and current md a measurement of the solar array temperature. It is consist of only two sample and hold circuits, two comparators, a flip-flop, and an integrator. The proposed MPPT algorithm is verified by the simulation and experimental.