Faculty Publications
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Item Improved SuDoKu reconfiguration technique for total-cross-tied PV array to enhance maximum power under partial shading conditions(Elsevier Ltd, 2019) Sai Krishna, G.; Moger, T.Mismatch losses ignore the performance of individual photovoltaic (PV) modules and cut back most of the power from the PV array. These losses mainly due to partial shading condition (PSC), are caused by the reduction of spacing between PV modules, passing clouds, and near buildings, etc. Several techniques are present in the literature to cut back the partial shading issues. One of the most effective methods is the reconfiguration techniques, namely reconfigure the location of PV modules in PV array so as to distribute partial shading effects and increase the maximum power output. This paper proposes an Improved SuDoKu reconfiguration pattern for 9×9 Total-Cross-Tied (TCT) PV array to enhance maximum power output under partial shading conditions. The main aim of this approach is to arrange the PV modules in TCT array according to the SuDoKu pattern without altering the electrical connections. Further, the performance of the proposed pattern is evaluated with different existing PV array configurations by comparing the Global Maximum Power Point (GMPP), Mismatch Losses (ML), Fill Factor (FF) and Efficiency (?). Based on the results of this paper, it is concluded that the proposed improved SuDoKu PV array arrangement enhances the global maximum power under all shading conditions. © 2019 Elsevier LtdItem Enhancement of maximum power output through reconfiguration techniques under non-uniform irradiance conditions(Elsevier Ltd, 2019) Sai Krishna, G.; Moger, T.Partial shading is one of the major drawback which diminishes the power output of the PV array. One of the effective methodologies is reconfiguration strategies, namely shifting the location of PV modules from one place to different places so as to distribute shading effects over the array to increase maximum power output under PSCs. This paper proposed two novel puzzle arrangements followed by Ken-Ken (KK) and Skyscraper (SS) for 4×4 total-cross-tied (TCT) PV array and increase maximum power under PSCs. In this approach, the PV modules in the TCT array is arranged according to Ken-Ken and Skyscraper arrangements without changing the electrical connections. Further, the performance of the proposed arrangements are investigated with different existing PV array configurations by comparing the global maximum power point (GMPP), the voltage at global maximum power point (VGMPP), mismatch losses (ML), fill-factor (FF), efficiency (?) and possible local peaks (PLP) under different shading patterns using Matlab-Simulink. An extensive simulation study is carried out on these configurations under different shading patterns as well as temperatures. Also, a comprehensive comparison has done for various reconfiguration schemes presented in literature. The result shows that the proposed arrangements are enhancing the global maximum power as compared to the other existing configurations. © 2019 Elsevier LtdItem Optimal SuDoKu Reconfiguration Technique for Total-Cross-Tied PV Array to Increase Power Output under Non-Uniform Irradiance(Institute of Electrical and Electronics Engineers Inc., 2019) Sai Krishna, G.; Moger, T.Partial shading condition drastically reduces the maximum power output of photovoltaic array. Partial shading occurs due to several factors, such as flying birds, trees, and passing clouds. Many ways can be mitigated partial shading problems in photovoltaic (PV) array. One among the way is reconfiguration techniques, namely reconfigure the location of PV modules in PV array based on irradiance levels in order to distribute shading effects and increasing maximum power. This paper proposed an optimal SuDoKu reconfiguration pattern for 9\times 9 total-cross-Tied (TCT) PV array to improve maximum power under partial shading conditions. In this approach, the physical location of PV modules in TCT array are rearranged based on optimal SuDoKu style without altering the electrical connections, so that the shading effects can distribute over the array. Further, the performance of proposed pattern investigated with existing SuDoKu pattern under different shading conditions by comparing the global maximum power point, mismatch losses, fill-factor, and efficiency using MATLAB-Simulink. Based on the results of this paper, it concluded that the proposed optimal SuDoKu reconfiguration arrangement is reducing the wiring arrangement and increasing the shading distribution over the array as compared to SuDoKu arrangement. © 1986-2012 IEEE.Item Enhanced power generation for total-cross-tied pv array using simulated annealing under partial shading conditions(John Wiley and Sons Inc, 2020) Sai Krishna, G.S.; Moger, T.Shade phenomena affect the PV module's power output, introduce multiple peak points in PV characteristics, and shorten the expected life cycle of the module. In order to prevent this issue, PV modules should reconfigure, namely, altering the electrical connections between PV modules based on the irradiance without changing their physical locations. As a result, the shading effects can distribute over the array and increase power output. This paper proposed a novel reconfiguration technique based on the simulated annealing algorithm to distribute shading impacts on 9×9 total-cross-tied (TCT) PV array. In this work, the proposed algorithm produces a reconfigured connection matrix for 9×9 TCT array that can minimize the current differences in each row and improve the power output. Various shading conditions have been taken to investigate the proposed technique by obtained global maximum power point (GMPP), current at GMPP, power loss, fill-factor, and efficiency. Further, the performance of the proposed technique is validated with other existing reconfiguration methods under partial shadings. In comparison with existing methods, the result shows that the proposed simulated annealing enhanced the power generation of the TCT array under all shading patterns. © The Institution of Engineering and Technology 2020.Item A novel adaptive dynamic photovoltaic reconfiguration system to mitigate mismatch effects(Elsevier Ltd, 2021) Sai Krishna, G.; Moger, T.Unequal solar irradiance of the Photovoltaic (PV) modules diminishes the PV array's maximum power output; this effect is due to Partial Shading Conditions (PSCs). There are a few technical options to fix this issue. One of these is the dynamic reconfiguration technique, which means that the electrical connections between the PV modules in the array are dynamically modified to spread shading effects and increase the power output. This paper proposed a novel adaptive reconfiguration method for 3×3 Total-Cross-Tied (TCT) PV array to enhance the maximum power under partial shading conditions. In this work, the PV module's electrical connections are altered dynamically with the proposed logic algorithm's help to maintain the identical row currents in the array. This technique is implemented on 3×3 size of an array using MATLAB and validated experimentally using OPAL-RT software. Further, the proposed technique performance is compared with the existing PV array connections such as Series-Parallel (SP), Total-Cross-Tied (TCT), Bridge-Link (BL), Honey-Comb (HC), and Shade Dispersion Positioning (SDP). Additionally, for different reconfiguration methods, revenue generation from energy savings is estimated. Based on the observations from the results, it is understood that the proposed technique enhanced the maximum power of the TCT array at a higher level as compared to the other PV array connections under PSCs. © 2021 Elsevier LtdItem Investigation of Power losses on Solar Photovoltaic Array Interconnections Under Mismatch Conditions(Springer, 2021) Sai Krishna, G.; Moger, T.The mismatch effect creates a difference between the sum of maximum power generated by individual Photovoltaic (PV) modules and the overall PV array power output. Mismatch effects can be classified into internal and external mismatch effects. Internal mismatch effect occurs because of factors such as manufacturing defects and ageing. The external effect occurs because of variations in solar irradiance and temperature. This paper presents the investigation of internal and external mismatch effects on various 5×4 Photovoltaic (PV) array interconnections such as series-parallel, total-cross-tied, bridge-link, honey-comb, hybrid SP-TCT, hybrid BL-TCT, along with proposed hybrid HC-TCT and hybrid HC-BL. Six mismatch case studies are considered in this paper to investigate the performance of PV array connections. Among the six cases, three cases are due to internal mismatch effects, and the remaining three cases belong to the external effects. In addition, the global maximum power point (GMPP), the voltage at GMPP, thermal voltage, power loss, fill-factor, efficiency (?), and possible local peaks (PLP) parameters are calculated and compared for each PV array connection under all case studies using Matlab-Simulink. Also, for each PV array connection, the revenue generation is calculated from energy savings under mismatch effects. The paper summary shows that TCT, HC-TCT, and HC-BL array connections delivered beneficial results under external effects, and TCT, HC, HC-TCT, and HC-BL provided superior results under internal effects. © 2021, The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd.