Mitigation of Hot-Spots in Photovoltaic Systems Using Distributed Power Electronics

Olalla, Carlos; Hasan, Md. Nazmul; Deline, Chris; Maksimović, Dragan

doi:10.3390/en11040726

Cited by 53 publications

(32 citation statements)

References 40 publications

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“…2(a). Another reason that hot-spotted PV modules strongly depends on the environmental parameters such as strong wind speed (eventually cools down PV surface and reduce hot-spotting impact [40]), humidity variations and the ambient temperature [16], therefore, with such environmental conditions, the MPPT tracking accuracy might differ meaningfully.…”

Section: A Examined Pv Modulesmentioning

confidence: 99%

“…Most recently, distributive MPPT method suggested by Coppola et al [15] and Olalla et al [16] are a conventional method to mitigate hot-spot in PV modules, with an approximate reduction up to 20 °C for small and medium hotspotting areas. On the other hand, Kim & Krein [17] show the "inadequateness" of the standard bypass diodes, the insertion of a series-connected switch are suited to interrupt the current flow during bypass activation process.…”

Section: Introductionmentioning

confidence: 99%

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Assessing MPPT Techniques on Hot-Spotted and Partially Shaded Photovoltaic Modules: Comprehensive Review Based on Experimental Data

Dhimish

2019

IEEE Trans. Electron Devices

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Hot-spotting is a reliability problem influencing photovoltaic (PV) modules, where a mismatched solar cell/cells heat up significantly and reduce the output power of the affected PV module. Therefore, in this paper, a succinct comparison of seven different state-of-the-art MPPT techniques are demonstrated, doing useful comparisons with respect to amount of power extracted, hence calculate their tracking accuracy. The MPPT techniques have been embedded into a commercial off-the-shelf MPPT unit, accordingly running different experiments on multiple hot-spotted PV modules. Furthermore, the comparison includes real-time long-term data measurements over several days and months of validation. Evidently, it was found that both fast changing MPPT (FC-MPPT) and the modified beta (M-Beta) techniques are best to use with PV modules affected by hot-spotted solar cells as well as during partial shading conditions, on average, their tracking accuracy ranging from 92% to 94%. Ultimately, the minimum tracking accuracy is below 93% obtained for direct PWM voltage controller (D-PWM-VC) MPPT technique.

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Section: A Examined Pv Modulesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessing MPPT Techniques on Hot-Spotted and Partially Shaded Photovoltaic Modules: Comprehensive Review Based on Experimental Data

Dhimish

2019

IEEE Trans. Electron Devices

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“…The higher resonant frequency f r was 164 kHz, and the prototype was operated at f s = 140 kHz with a dead time period of 0.4 µs. sufficient to preclude loss in annual energy yield in most cases [35,36]. As long as panels are installed in a proper location, severe shading conditions rarely occur.…”

Section: Prototypementioning

confidence: 99%

LLC Resonant Voltage Multiplier-Based Differential Power Processing Converter Using Voltage Divider with Reduced Voltage Stress for Series-Connected Photovoltaic Panels under Partial Shading

2019

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Partial shading on photovoltaic (PV) strings consisting of multiple panels connected in series is known to trigger severe issues, such as reduced energy yield and the occurrence of multiple power point maxima. Various kinds of differential power processing (DPP) converters have been proposed and developed to prevent partial shading issues. Voltage stresses of switches and capacitors in conventional DPP converters, however, are prone to soar with the number of panels connected in series, likely resulting in impaired converter performance and increased circuit volume. This paper proposes a DPP converter using an LLC resonant voltage multiplier (VM) with a voltage divider (VD) to reduce voltage stresses of switches and capacitors. The VD can be arbitrarily extended by adding switches and capacitors, and the voltage stresses can be further reduced by extending the VD. Experimental verification tests for four PV panels connected in series were performed emulating partial shading conditions in a laboratory and outdoor. The results demonstrated the proposed DPP converter successfully precluded the negative impacts of partial shading with mitigating the voltage stress issues.

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“…PV array reconfiguration can be obtained by means of a reconfigurable switch matrix made of MOSFETs or of electromechanical relays. In [26][27][28][29][30], it has been shown that distributed converters can improve system reliability by reducing the occurrence of hot spots. In fact, reliability represents a crucial aspect to take into account in PV applications.…”

Section: Introductionmentioning

confidence: 99%

On the Link between the Operating Point and the Temperature Distribution in PV Arrays Working under Mismatching Conditions

Costanzo

Vitelli

2018

International Journal of Photoenergy

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Mismatching operating conditions negatively affect the extracted energy in photovoltaic (PV) systems. They may also lead to dangerous localized heating phenomena (hot spots) that can cause, in turn, accelerated ageing and reduced reliability. Since the adoption of bypass diodes or smart active switches does not prevent the occurrence of hotspots, it is necessary to investigate alternative strategies. A promising solution is represented by the proper regulation of the operating point of the PV cells in the current vs. voltage (I-V) or power vs. voltage (P-V) planes when mismatching conditions occur. In particular, in this paper, the existence of operating points allowing a suitable compromise between maximization of the extracted power and minimization of thermal stresses, due to hot spots, is experimentally evidenced. Experimental results highlighting the link existing between the operating point in the I-V plane and the PV cell temperature distribution under uniform and mismatching operating conditions are presented and discussed. On the basis of the obtained experimental results, it is possible to state that, when mismatching conditions occur, it is mandatory to properly choose the operating point: the global maximum power point may not be the best operating point. Hence, it is crucial to gain information about the eventual occurrence of mismatching conditions in order to be able to properly choose the best operating point. Therefore, another crucial aspect that is evidenced in this paper is represented by the fact that the detection of the occurrence of mismatching conditions, based on the analysis of the shape of the I-V and/or P-V characteristics, is effective only if the analysis is carried out for both positive and negative voltages.

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Mitigation of Hot-Spots in Photovoltaic Systems Using Distributed Power Electronics

Cited by 53 publications

References 40 publications

Assessing MPPT Techniques on Hot-Spotted and Partially Shaded Photovoltaic Modules: Comprehensive Review Based on Experimental Data

Assessing MPPT Techniques on Hot-Spotted and Partially Shaded Photovoltaic Modules: Comprehensive Review Based on Experimental Data

LLC Resonant Voltage Multiplier-Based Differential Power Processing Converter Using Voltage Divider with Reduced Voltage Stress for Series-Connected Photovoltaic Panels under Partial Shading

On the Link between the Operating Point and the Temperature Distribution in PV Arrays Working under Mismatching Conditions

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