• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.220-227
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• 2012

The maximum power point tracking(MPPT) is important part pf PV generating system, because of nonlinear characteristic of PV array. Many MPPT algorithms have been developed and proposed, but partially shaded in PV generating system, these algorithms can not track maximum power point. This paper explains the partially shaded conditions in the PV generating system and describes a novel new MPPT algorithm. To verify the proposed novel algorithm, PSIM simulation tool is used in this paper, and proper 3kW PV module modeling is made. As a result, the right maximum power point(11PP) of PV PCS can be tracked directly under shading effect for any mismatched condition in solar array.

• Journal of Power Electronics
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• v.16 no.1
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• pp.287-296
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• 2016

Conventional maximum power point tracking (MPPT) methods are ineffective under partially shaded conditions because multiple local maximum can be exhibited on power-voltage characteristic curve. This study proposes an improved cuckoo search (ICS) MPPT method after investigating the cuckoo search (CS) algorithm applied in solving multiple MPPT. The algorithm eliminates the random step in the original CS algorithm, and the conception of low-power, high-power, normal and marked zones are introduced. The adaptive step adjustment is also realized according to the different stages of the nest position. This algorithm adopts the large step in low-power and marked zones to reduce search time, and a small step in high-power zone is used to improve search accuracy. Finally, simulation and experiment results indicate that the promoted ICS algorithm can immediately and accurately track the global maximum under partially shaded conditions, and the array output efficiency can be improved.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.308-310
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• 2005

In recent years, the research and development for the photovoltaic(PV) energy system are making rapidly progress around the world and specially this country, too due the deregulation law for the renewable energy system seems to be born sooner or later. In PV generation system, the partially shaded PV array is the one of the worst case which reduces the efficiency of the total PV generation system. The partial shaded condition is the result of shadowing by cloud and dust building of on the surface of the panel. Some structural elements, such as antennas, booms etc. is also the reason of the shadowing. Even if only a small part of PV is shaded, the overall generation power of PV is significantly decreased. Therefore, several researchers who are focusing on the PV generation system take a time for the research related with the shadowing problem of PV array. In this paper, authors have developed the method which users can achieved the modeling of partially shaded PV array with. With several papers authors have already announced the availability of the EMTDC/PSCAD PV panel model component. This research result is the developed version of the previous papers.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.4
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• pp.281-292
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• 2016

The proposed scheme is based on the modified perturb and observe (P&O) algorithm combined with the sliding mode technique. A modified P&O algorithm based sliding mode controller is developed to study the effects of partial shade, temperature, and insolation on the performance of maximum power point tracking (MPPT) used in photovoltaic (PV) systems. Under partially shaded conditions and temperature, the energy conversion efficiency of a PV array is very low, leading to significant power losses. Consequently, increasing efficiency by means of MPPT is particularly important. Conventional techniques are easy to implement but produce oscillations at MPP. The proposed method is applied to a model to simulate the performance of the PV system for solar energy usage, which is compared to the conventional methods under non-uniform insolation improving the PV system utilization efficiency and allowing optimization of the system performance. The modified perturb and observe sliding mode controller successfully overcomes the issues presented by non-uniform conditions and tracks the global MPP. Compared to MPPT techniques, the proposed technique is more efficient; it produces less oscillation at MPP in the steady state, and provides more precise tracking.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.317-320
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• 2009

Under partial shading condition, the multiple local maxima can be existed on the output characteristics of PV array. In case of the conventional MPPTs (i.e P&O or IncCond), the failure of maximum power point tracking could be occurred under partial shading condition(PSC). The problems are deduced by the analysis of conventional MPPTs. In this paper, a real maximum power point tracking for PV array under partially shaded condition is proposed. And proposed MPPT is analyzed by case study. It is confirmed by simulation results that the proposed MPPT can track the real MPP under partial shading condition.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.17-22
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• 2011

There are some degradation factors for amorphous silicon solar cells. Light inducing is one of the factor that explained by Staebler-Wronski effect. Also, hotspot heating could be the reason that makes amorphous silicon solar cell degrade. Hotspot heating is occurred when a solar cell is shaded so this work is investigated into two types of shading condition and how these affect to solar cell differently. Reduced irradiance for whole cell and partially shaded as 0($W/m^2$) while the other part of cell is soaking as 1000($W/m^2$) of irradiance are two conditions that are experimented. The two types of shading show different characteristics of degradations. The result shows that partially shaded cell dropped maximum powerless and slower. Also sudden drop points have shown that should be concerned to decide the number of cells for a string. Otherwise, the current through a shaded cell might flow more than cell's capability. It makes cell and module damaged. This work would help to manufacture modules.

• Journal of Power Electronics
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• v.14 no.4
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• pp.722-732
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• 2014

The power-voltage (P-V) curve of photovoltaic (PV) arrays connected in parallel to bypass diodes would have several local maximum power points (LMPP) under partial shading conditions (PSC). Conventional maximum power point tracking (MPPT) methods fail to search for the global maximum power point (MPP) because the searched peak point may remain at the LMPP on the P-V curve under PSC. This study proposes an improved MPPT algorithm to ensure that PV arrays operate at global maximum power point (GMPP) under PSC. The proposed algorithm is based on a critical study and a series of observations of PV characteristics under PSC. Results show the regularity of voltage interval between LMPPs. The algorithm has the advantages of rapidly reaching GMPP, maintaining stability, and recovering GMPP quickly when the operating condition changes. Simulation and experimental results demonstrate the feasibility of the proposed algorithm.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.248-249
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• 2012

PV 어레이에 부분적으로 음영이 발생하면 그 P-V 특성은 여러 개의 MPP를 보인다. 이런 상황에서는 global MPP를 찾아내기 위한 특수한 기법이 요구된다. 본 논문에서는 기존에 제안된, 부분 음영 조건 발생 시 global MPP를 찾아내는 MPPT 기법을 개선하고 실험을 통하여 유효성을 검증한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.94-102
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• 2020

Considering that the output voltage and current of a single PV panel are limited in PV power generation, a PV array should be constructed by connecting several PV panels in series and parallel to meet the required voltage/power levels for power generation capacity. When a PV array is partially shaded, the maximum power generation depends on the configuration of a PV array and the presence or absence of blocking diodes. This study considers six PV array configurations and the presence or absence of blocking diodes. An optimum connection structure was proposed to maximize power generation in a partial shadow condition. Results were verified through simulation and an experiment.

• Korean Journal of Materials Research
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• v.25 no.4
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• pp.196-201
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• 2015

This paper presents the impact of partial shading on $CuIn_xGa_{(1-x)}Se_2(CIGS)$ photovoltaic(PV) modules with bypass diodes. When the CIGS PV modules were partially shaded, the modules were under conditions of partial reverse bias. We investigated the characterization of the bypass diode and solar cell properties of the CIGS PV modules when these was partially shaded, comparing the results with those for a crystalline silicon module. In crystalline silicon modules, the bypass diode was operated at a partial shade modules of 1.67 % shading. This protected the crystalline silicon module from hot spot damage. In CIGS thin film modules, on the other hand, the bypass diode was not operated before 20 % shading. This caused damage because of hotspots, which occurred as wormlike defects in the CIGS thin film module. Moreover, the bypass diode adapted to the CIGS thin film module was operated fully at 60% shading, while the CIGS thin film module was not operated under these conditions. It is known that the bypass diode adapted to the CIGS thin film module operated more slowly than that of the crystalline silicon module; this bypass diode also failed to protect the module from damage. This was because of the reverse saturation current of the CIGS thin film, $1.99{\times}10^{-5}A/cm^2$, which was higher than that of crystalline silicon, $8.11{\times}10^{-7}A/cm^2$.