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 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 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.Item A non-isolated bidirectional high gain integrated multiport converter for grid tied solar PV fed telecom load(John Wiley and Sons Inc, 2023) Sheeja, V.; Kalpana, R.; Singh, B.; Subramaniam, U.; Muhibbullah, M.A multiport converter (MPC) with a non-isolated high gain bidirectional port is proposed for the grid integration of solar photovoltaic array (SPA) fed telecommunication load. The SPA along with a battery energy storage (BES) meets the power demand of the telecom DC load and the excess/deficit power is exchanged with AC grid. The MPC feeds the DC link of a voltage source converter for bidirectional operation with the AC grid. The small signal analysis of the converter shows that its operation is stable. The SPA, BES, and telecommunication load are rated for lower voltages, consecutively reducing the complexity with series-connected SPA. The proposed MPC possesses the merits of high voltage gain, reduced inductor size, and reduced number of components. Moreover, a power flow management algorithm is devised for the proposed converter that regulates the DC voltage at the telecom load and ensures smooth power flow control among various ports. The MPC is able to operate at various modes by controlling the ports independently. The converter performance during steady state and dynamic operating conditions under various modes are analyzed with detailed simulation studies. An experimental prototype is developed and test results are demonstrated to prove the viability of the designed converter. © 2022 The Authors. IET Power Electronics published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.Item An innovative competence square technique for PV array reconfiguration under partial shading conditions(Taylor and Francis Ltd., 2024) Kumar, D.; Raushan, R.The power generated by the photovoltaic (PV) array reduces drastically due to irregular solar irradiation. Shading pattern, shaded area, and array configuration are the main causes of reduction in power generation. The electrical characteristics of the modules in the array possess several peaks due to the fact that they produce distinct row currents and have various peaks in their electrical characteristics. Therefore, an appropriate technique is needed to minimize the row current difference that leads to maximum power generation at a higher level. This can be achieved by array reconfiguration; therefore, an Innovative Competence Square technique is proposed in this paper. The proposed technique disperses the shade effectively over the entire array by displacing the modules. The MATLAB simulation was run under three distinct shading conditions to validate the proposed technique’s performance, and it has been compared to the Competence Square technique and TCT interconnection. The technique’s benefits can be seen in terms of increased power generation, FF, and reduced mismatch losses. © 2023 Informa UK Limited, trading as Taylor & Francis Group.Item A Simple Primary Key Algorithm Based Shade Dispersion Method for Maximizing PV Power Generation under Partial Shading Conditions(Institute of Electrical and Electronics Engineers Inc., 2024) Koothu Kesavan, P.K.; Karthikeyan, A.; Kumar, M.; Mandal, S.The output power generation of a photovoltaic (PV) array reduces under partial shading, resulting in multiple local maxima in the PV characteristics and inaccurate tracking of the global maximum power point (GMPP). Various interconnection schemes are available to reduce power losses under partial shading. In this study, a primary key algorithm is proposed for distributing shading across an array. This method is suitable for any n×n PV array configuration and involves fewer calculations and variables, leading to reduced computational complexity. The power generations of a 9×9 PV array under four different shading conditions were compared with the configurations of: total cross-tied (TCT) and Su Du Ku, physical relocation and fixed column position of modules with fixed electrical connection (PRFCPM-FEC), and magic square (MS) and improved-odd-even-prime (IOEP). The advantage of the proposed method is that once the primary key elements are obtained, the remaining array elements are numbered in a simpler manner. The results obtained using the proposed arrangement show that the power is enhanced with reference to the TCT and is comparable to the Su Do Ku, PRFCPM-FEC, MS, and IOEP reconfigurations. © 2024 China Machinery Industry Information Institute.Item Cyclic back shift method for maximizing PV array power under partial shading(Springer Science and Business Media Deutschland GmbH, 2025) Ramesh, D.; Karthikeyan, K.Partial shading leads to reduction in power output and efficiency of photovoltaic (PV) systems. The physical arrangement of PV modules without changing electrical circuitry plays vital role in reducing the effects caused by partial shading. This paper presents a cyclic back shift (CBS) method to enhance the PV power under partial shading conditions (PSCs). In this method, relocation of modules is based on row positions of modules in a particular column. The proposed CBS method is cost-effective, simple and applicable for both square and non-square array. The proposed CBS method is implemented on 9×9 PV array and tested in both software (20.25 kW system) and hardware (0.81 kW system) environments under various shading patterns. The performance parameters such as fill factor (FF), mismatch loss (ML) and efficiency (?) are plotted. Further, a comparative analysis is carried between the proposed CBS method, total cross tied (TCT) and different existing reconfiguration schemes. From the experimental results, it is observed that the proposed CBS method is able to enhance the GMPP by minimum 11.83% under shading pattern-II and maximum of 18.78 under shading pattern-III compared to TCT configuration. Hence, the CBS method of module arrangement is an effective solution in reducing the partial shading effects. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.