Manjunath Matam

@ucf.edu

Assistant Professor and Solar and Energy Integration Division
University of Central Florida

Manjunath Matam


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https://researchid.co/mycolabfactory

EDUCATION

B.Tech, M.Tech, Ph.D.

RESEARCH, TEACHING, or OTHER INTERESTS

Renewable Energy, Sustainability and the Environment, Electrical and Electronic Engineering
13

Scopus Publications

361

Scholar Citations

8

Scholar h-index

8

Scholar i10-index

Scopus Publications

  • Comparing Outdoor to Indoor Performance for Bifacial Modules Affected by Polarization-Type Potential-Induced Degradation
    Dylan J. Colvin, Cécile Molto, Ryan M. Smith, Manjunath Matam, Peter Hacke, Fang Li, Brent A. Thompson, James Barkaszi, Govindasamy Tamizhmani, Hubert P. Seigneur
    Solar, 2025
    Bifacial photovoltaic (PV) modules have the advantage of using light reflected off of the ground to contribute to power production. Predicting the energy gain is challenging and requires complex models to do so accurately. Often, module degradation over time is neglected in models for the sake of simplicity or is underestimated. Comparing outdoor and indoor current–voltage (I–V) performance for bifacial modules is more challenging than for monofacial modules, as there are additional variables to consider such as rear albedo non-uniformity, cell mismatch, and their effects on temperature. This challenge is compounded when heterogeneous degradation modes occur, such as polarization-type potential-induced degradation (PID-p). To examine the effects of PID-p on I–V predictions using an empirical data-driven approach, 16 bifacial PERC modules are installed outdoors on racks with different albedo conditions. A subset is exposed to high-voltage biases of −1500 V or +1500 V. Outdoor data are traced at irradiance ranges of 150–250 W/m2, 500–600 W/m2, and 900–1000 W/m2. These curves are corrected using control module temperature, wire resistivity, and module resistance measured indoors. We examine several methods to transform indoor I–V curves to accurately, and more simply than existing methods, approximate outdoor performance for bifacial modules without and with varying levels of PID-p degradation. This way, bifacial performance modeling can be more accessible and informed by fielded, degraded modules. Distributions of percent errors between indoor and outdoor performance parameters and Mean Absolute Percent Errors (MAPEs) are used to assess method quality. Results including low-irradiance data (150–250 W/m2) are discussed but are filtered for quantifying method quality as these data introduce substantial errors. The method with the most optimal tradeoff between low MAPE and analysis simplicity involves measuring the front side of a module indoors at an irradiance equal to plane-of-array irradiance plus the product of module bifaciality and albedo irradiance. This method gives MAPE values of 1–6.5% for non-degraded and 1.6–5.9% for PID-p degraded module performance.
  • Characterization of Field-Exposed Photovoltaic Modules Featuring Signs of Contact Degradation
    Max Liggett, Dylan J. Colvin, Andrew Ballen, Manjunath Matam, Hubert P. Seigneur, Mengjie Li, Andrew M. Gabor, Philip J. Knodle, Craig J. Neal, Sudipta Seal, Daniel Riley, Bruce H. King, Peter Michael, Laura S. Bruckman, Roger H. French, Kristopher O. Davis
    IEEE Journal of Photovoltaics, 2025
    This work investigates several photovoltaic (PV) modules that have shown signs of metal contact corrosion due to field exposure in a hot and humid climate. This includes two multicrystalline silicon aluminum back surface field systems with 10 and 14 years of exposure and one monocrystalline silicon passivated emitter and rear cell system with four years of exposure. A comprehensive, multiscale characterization process is used to evaluate these PV modules in great detail. Current–voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I-V$</tex-math></inline-formula>), Suns-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\text{OC}}$</tex-math></inline-formula> measurements, electroluminescence imaging, infrared imaging, and ultraviolet fluorescence imaging were performed, and locations of interest were cored and analyzed using cross-sectional scanning electron microscopy (SEM). A rigorous, quantitative analysis procedure for the cross-sectional SEM images is proposed and implemented. Careful characterization does reveal that some of these PV modules do indeed exhibit the same classic signs of acetic-acid-based corrosion of the glass frit that is present at the silver/silicon interface, which have been observed previously in PV modules exposed to damp heat in an environmental chamber.
  • PV Modules Temperature Variation and Patterns in Medium and Utility-Scale Floating PV Systems
    Manjunath Matam, Bill Sekulic
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2024
    This paper presents the preliminary results and findings of the four operational Floating PV systems across the USA. At each site, temperature of five PV modules located at North-West, North-East, Middle, South-West, and, South-East have been monitored through the Resistant Temperature Detector (RTD) sensors. Three RTDs were attached to each PV module on the rear-side along the diagonal at top, middle and bottom cells. The preliminary results reveal wide temperature differences among the inter and intra PV modules. Besides this, wave pattern temperatures were observed in a few PV modules. The final results, findings, and, factors responsible will be investigated during the next few months.
  • Investigating Contact Corrosion in Field-Exposed Photovoltaic Modules: A Multimodal Approach
    Max Liggett, Dylan J. Colvin, Andrew Ballen, Balaashwin Babu, William C. Olrjen, Xuanji Yu, Maniunath Matam, Hubert P. Seigneur, Mengjie Li, Andrew M. Gabor, Philip J. Knodle, Craig J. Neal, Sudipta Seal, Daniel Rilev, Bruce H. King, Peter Michael, Danvers Johnston, Laura S. Bruckman, Roger H. French, Kristopher O. Davis
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2024
    The solar energy industry is rapidly expanding and constantly modifying design, and bill of materials. The prolific advancement of photovoltaic (PV) technology only emphasizes the importance of field research for ensuring reliability and validating the accelerated aging methodologies that allow researchers to avoid waiting 20 - 30 years for the natural failure of the device. In this research, we take a multiscale analytical approach to investigate fielded PV modules that were showing signs of contact corrosion. To assess module-level performance, we conducted current-voltage (IV) and Suns-VOC measurements, electrolumi-nescence (EL) imaging, infrared (IR) imaging, and ultraviolet fluorescence (UVF) photography imaging on multicrystalline silicon (multi-Si) and monocrystalline silicon (mono-Si) modules which operated in a hot and humid climate. Additionally, we demonstrate a method for quantitative characterization of PV front contacts with image processing of SEM cross-sectional images.
  • Simulated Impact of Shortened Strings in Commercial and Utility-Scale Photovoltaic Arrays
    Ryan M. Smith, Manjunath Matam, Hubert Seigneur
    Energies, 2023
    The deliberate removal of photovoltaic modules from a string can occur for various reasons encompassing maintenance, measurements, theft, or failure, reducing that string length relative to others when replacement modules are not available and there are not any viable alternative makes and models that could be inserted. This phenomenon, delineated in our prior experimentally validated research, manifests two significant effects: (1) a shift in the ideal maximum power point and (2) the induction of potentially substantial reverse currents in the shortened strings at open-circuit voltage, VOC. However, the scalability and asymptotic limits of these observed behaviors concerning array size remained undetermined. In this study, we elucidate the operational dynamics of such arrays by manipulating two mismatch-contributing variables in simulated arrays of up to 900 strings: the number of removed modules per string (indicative of the level of mismatch, ranging up to 5) and the quantity of shortened strings (1 to 60). Simulation outcomes underscore that mismatch severity impacts array operation more than the proportion of shortened strings. This research delves into the practical ramifications of operating with shortened strings, including implications for low-irradiance operation and the manifestation of deleterious reverse currents (&gt;35 A in specific cases), emphasizing the need for careful array configuration for optimal performance and safety in these implementations.
  • Review of Potential-Induced Degradation in Bifacial Photovoltaic Modules
    Cécile Molto, Jaewon Oh, Farrukh Ibne Mahmood, Mengjie Li, Peter Hacke, Fang Li, Ryan Smith, Dylan Colvin, Manjunath Matam, Christopher DiRubio, Govindasamy Tamizhmani, Hubert Seigneur
    Energy Technology, 2023
    Bifacial modules are increasingly deployed in the field and are expected to represent half of the market share within 10 years. Their rear structure differs from monofacial modules to allow additional light absorption. However, it brings new reliability challenges to address. In particular, the risk of potential‐induced degradation (PID) is increased as both module sides are impacted. Different PID processes have been identified in the literature: shunting type (PID‐s), polarization type (PID‐p), Na penetration type, and corrosion type (PID‐c). Their occurrence depends on the photovoltaic system configuration as well as the module's materials. Apart from PID‐s, PID processes are not well understood and extensive research is needed to elucidate the PID scenario and underlying mechanisms. Herein, current knowledge about PID processes and their impact on the main bifacial modules in the market are gathered with the aim to guide future research. Bifacial module technologies and leakage current paths leading to PID are described. Indoor and outdoor PID testing methods are detailed. For each bifacial module technology, the PID processes are investigated with their indicators, mechanism and recovery process. PID‐impacting factors and limitation solutions are finally reported and a state of the art on PID modeling is presented.
  • Characterization of Field Exposed Photovoltaic Modules Featuring Signs of Contact Degradation
    Max Liggett, Dylan J. Colvin, Balaashwin Babu, William C. Oltjen, Xuanji Yu, Manjunath Matam, Hubert P. Seigneur, Mengjie Li, Andrew M. Gabor, Philip J. Knodle, Craig J. Neal, Sudipta Seal, Laura S. Bruckman, Roger H. French, Kristopher O. Davis
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2023
    As the solar energy industry expands, the reliability and lifespan of photovoltaic (PV) modules have become increasingly important to ensure commercial viability for large-scale applications. To improve reliability and performance, it is necessary to better understand modes of failure through accelerated aging tests, which can identify degradation mechanisms that take a long time to manifest. This work investigates contact corrosion of fielded PV modules using a multi-scale analytical approach. Current-voltage (IV) and Suns-VOC measurements, electroluminescence (EL) imaging, Infrared (IR) imaging, and Ultraviolet Fluorescence (UVF) photography imaging were performed on multicrystalline silicon (multi-Si) and monocrystalline silicon (mono-Si) modules installed in a hot and humid climate. Subsequently, locations of interest were cored from the modules and analyzed using cross-sectional scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).
  • PV Module Degradation Due to Frequent and Prolonged Inverter Clipping: A Preliminary Study
    Manjunath Matam, Ryan M. Smith, Hubert Seigneur
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2022
    Photovoltaic (PV) plant owners usually install PV arrays that are larger than the inverter's rated capacity. With a DC to AC ratio greater than unity, the PV array occasionally operates at a sub-optimal point imposed by the inverter. This is common practice in the USA, and is known as ‘clipping.’ Clipping may be implemented by operating the array at voltages below the maximum power point (MPP), or more commonly, above the MPP. Advantages of clipping operation are the utilization of an inverter's full capacity and improved financial break-even time. Regulatory requirements may also mandate reduced power output from an array in a forced clipping situation known as curtailment. However, the long-term impact on the PV array's life, array degradation, aging, hot spots, and module warranty has not been adequately investigated for prolonged off-MPP operation. This paper presents preliminary studies of the potential long-term impact of clipping on the PV array beyond energy production. For this study, the module and string level data, primarily through I-V curves and IR imaging, is investigated along with analysis of inverter electrical data. This preliminary work shows that the PV array exhibits significantly different temperature signatures if operated below the maximum power point as opposed to above, conditions which could be experienced when clipping. In addition, the initial data revealed unique IR imaging patterns: checkerboard patterns at voltages below the MPP and uniform elevated temperature patterns at voltages above the MPP.
  • Mismatch losses in a PV system due to shortened strings
    Ryan M. Smith, Manjunath Matam, Hubert Seigneur
    Energy Conversion and Management, 2021
  • An Algorithm for Filtering the Time-series I-V curves of a PV plant
    Manjunath Matam, Hubert Seigneur
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2021
    This paper presents a Machine learning-based algorithm to filter the time-series I-V curves collected from a PV plant. The filter’s objective is detecting and segregating the normal looking I-V curves from the abnormal ones. A non-linear Machine learning regression model was used for this purpose. Initially the model is trained on the labeled data and then tested on a unknown data. The proposed model is trained and tested on the time-series I-V curves of experimental PV strings installed in the field. The obtained model coefficients, results are discussed in the paper.
  • PV Array IV Curves: Why We See Them the Way We Do?
    Manjunath Matam
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2020
  • Detecting Abnormal Profiles in the Database of a PV plant through Programmatic Comparison of per Unit Profiles
    Manjunath Matam, Joseph Walters
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2020
  • Re-looking the Shunt-Resistance Calculating Methodologies of IV-curves
    Manjunath Matam, Hubert Seigneur, Joseph Walters
    Conference Record of the IEEE Photovoltaic Specialists Conference, 2020

RECENT SCHOLAR PUBLICATIONS

  • FPGA-Based Hardware Accelerator with RISC-V Processor for Real-Time CNN Inference on ECG Signals
    PR Kulkarni, M Manjunath, PR Dhotar, U Mishra, SA Bandikatte, ...
    2025 9th International Conference on Computational System and Information … , 2025
    2025
  • Comparing Outdoor to Indoor Performance for Bifacial Modules Affected by Polarization-Type Potential-Induced Degradation
    DJ Colvin, C Molto, RM Smith, M Matam, P Hacke, F Li, BA Thompson, ...
    Solar 5 (3), 43 , 2025
    2025
  • Gaining Fundamental Understanding of Critical Failure Modes and Degradation Mechanisms in Fielded Photovoltaic Modules via Multiscale Characterization
    KO Davis, DJ Colvin, M Liggett, BA Thompson, SN Venkat, J Raby, ...
    2025 IEEE 53rd Photovoltaic Specialists Conference (PVSC), 1367-1367 , 2025
    2025
  • Characterization of Field-Exposed Photovoltaic Modules Featuring Signs of Contact Degradation
    M Liggett, DJ Colvin, A Ballen, M Matam, HP Seigneur, M Li, AM Gabor, ...
    IEEE Journal of Photovoltaics , 2025
    2025
    Citations: 7
  • Quantifying and Valuing Fundamental Characteristics and Benefits of Floating PV Systems
    CMC Kettles, M Matam, D Chasar, RR Hernandez, B Sekulic, AE Cagle, ...
    Univ. of Central Florida, Orlando, FL (United States) , 2024
    2024
    Citations: 1
  • PV Modules Temperature Variation and Patterns in Medium and Utility-Scale Floating PV Systems
    M Matam, B Sekulic
    2024 IEEE 52nd Photovoltaic Specialist Conference (PVSC), 1354-1356 , 2024
    2024
    Citations: 1
  • Simulated Impact of Shortened Strings in Commercial and Utility-Scale Photovoltaic Arrays
    RM Smith, M Matam, H Seigneur
    Energies 16 (21), 7222 , 2023
    2023
    Citations: 2
  • Review of potential‐induced degradation in bifacial photovoltaic modules
    C Molto, J Oh, FI Mahmood, M Li, P Hacke, F Li, R Smith, D Colvin, ...
    Energy Technology 11 (4), 2200943 , 2023
    2023
    Citations: 45
  • High-Resolution Floating Solar PV Data
    M Matam, RR Hernandez, B Sekulic, AE Cagle, D Jordan, D Chasar, ...
    DOE Open Energy Data Initiative (OEDI); University of Central Florida … , 2022
    2022
    Citations: 3
  • PV module degradation due to frequent and prolonged inverter clipping: A preliminary study
    M Matam, RM Smith, H Seigneur
    2022 IEEE 49th Photovoltaics Specialists Conference (PVSC), 0596-0603 , 2022
    2022
    Citations: 4
  • Mismatch losses in a PV system due to shortened strings
    RM Smith, M Matam, H Seigneur
    Energy Conversion and Management 250, 114891 , 2021
    2021
    Citations: 14
  • An Algorithm for Filtering the Time-series IV curves of a PV plant
    M Matam, H Seigneur
    2021 IEEE 48th Photovoltaic Specialists Conference (PVSC), 0147-0149 , 2021
    2021
    Citations: 2
  • Mismatch Losses in Simulated Commercial and Utility-scale PV Arrays due to Shortened Strings
    RM Smith, M Matam, H Seigneur
    Energy Conversion and Management 250 , 2021
    2021
  • Re-looking the shunt-resistance calculating methodologies of iv-curves
    M Matam, H Seigneur, J Walters
    2020 47th IEEE Photovoltaic Specialists Conference (PVSC), 1887-1889 , 2020
    2020
    Citations: 1
  • PV Array IV Curves: Why We See Them The Way We Do?
    M Matam
    2020 47th IEEE Photovoltaic Specialists Conference (PVSC), 1578-1580 , 2020
    2020
    Citations: 6
  • Detecting abnormal profiles in the database of a pv plant through programmatic comparison of per unit profiles
    M Matam, J Walters
    2020 47th IEEE Photovoltaic Specialists Conference (PVSC), 1534-1536 , 2020
    2020
    Citations: 5
  • Data-integrity checks and balances in monitoring of a solar pv system
    M Matam, J Walters
    2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 1276-1281 , 2019
    2019
    Citations: 8
  • Experimental methods to replicate power loss of pv modules in the field for the purpose of fault detection algorithm development
    J Walters, H Seigneur, E Schneller, M Matam, M Hopwood
    2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 1410-1413 , 2019
    2019
    Citations: 4
  • Performance improvement of dynamic PV array under partial shade conditions using M 2 algorithm
    M Manjunath, B Venugopal Reddy, B Lehman
    IET Renewable Power Generation 13 (8), 1239-1249 , 2019
    2019
    Citations: 37
  • Converter-less mppt for rural area applications
    M Manjunath, BV Reddy
    2018 IEEE International Conference on Power Electronics, Drives and Energy … , 2018
    2018
    Citations: 1

MOST CITED SCHOLAR PUBLICATIONS

  • Improved performance of dynamic photovoltaic array under repeating shade conditions
    M Matam, VR Barry
    Energy conversion and management 168, 639-650 , 2018
    2018
    Citations: 68
  • Optimized Reconfigurable PV array based Photovoltaic water-pumping system
    M Matam, VR Barry, AR Govind
    Solar Energy 170, 1063-1073 , 2018
    2018
    Citations: 60
  • Review of potential‐induced degradation in bifacial photovoltaic modules
    C Molto, J Oh, FI Mahmood, M Li, P Hacke, F Li, R Smith, D Colvin, ...
    Energy Technology 11 (4), 2200943 , 2023
    2023
    Citations: 45
  • Performance improvement of dynamic PV array under partial shade conditions using M 2 algorithm
    M Manjunath, B Venugopal Reddy, B Lehman
    IET Renewable Power Generation 13 (8), 1239-1249 , 2019
    2019
    Citations: 37
  • Consumer Behaviour towards Electricity–a field study
    M Manjunath, P Singh, A Mandal, GS Parihar
    Energy Procedia 54, 541-548 , 2014
    2014
    Citations: 35
  • Variable size dynamic PV array for small and various DC loads
    M Matam, VR Barry
    Solar Energy 163, 581-590 , 2018
    2018
    Citations: 23
  • On-line health monitoring of PV plants
    M Manjunath, BV Reddy, Y Zhao, B Lehman
    2017 IEEE Energy Conversion Congress and Exposition (ECCE), 4061-4068 , 2017
    2017
    Citations: 17
  • Mismatch losses in a PV system due to shortened strings
    RM Smith, M Matam, H Seigneur
    Energy Conversion and Management 250, 114891 , 2021
    2021
    Citations: 14
  • Data-integrity checks and balances in monitoring of a solar pv system
    M Matam, J Walters
    2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 1276-1281 , 2019
    2019
    Citations: 8
  • On-line global maximum power point (GMPP) identification of solar PV plants
    M Manjunath, BV Reddy, Y Zhao, B Lehman
    2018 IEEE Applied Power Electronics Conference and Exposition (APEC), 1109-1114 , 2018
    2018
    Citations: 8
  • Optimized reconfigurable solar PV battery charger using relay switching matrix
    M Manjunath, BV Reddy, GA Reddy
    2015
    Citations: 8
  • Characterization of Field-Exposed Photovoltaic Modules Featuring Signs of Contact Degradation
    M Liggett, DJ Colvin, A Ballen, M Matam, HP Seigneur, M Li, AM Gabor, ...
    IEEE Journal of Photovoltaics , 2025
    2025
    Citations: 7
  • PV Array IV Curves: Why We See Them The Way We Do?
    M Matam
    2020 47th IEEE Photovoltaic Specialists Conference (PVSC), 1578-1580 , 2020
    2020
    Citations: 6
  • Detecting abnormal profiles in the database of a pv plant through programmatic comparison of per unit profiles
    M Matam, J Walters
    2020 47th IEEE Photovoltaic Specialists Conference (PVSC), 1534-1536 , 2020
    2020
    Citations: 5
  • PV module degradation due to frequent and prolonged inverter clipping: A preliminary study
    M Matam, RM Smith, H Seigneur
    2022 IEEE 49th Photovoltaics Specialists Conference (PVSC), 0596-0603 , 2022
    2022
    Citations: 4
  • Experimental methods to replicate power loss of pv modules in the field for the purpose of fault detection algorithm development
    J Walters, H Seigneur, E Schneller, M Matam, M Hopwood
    2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 1410-1413 , 2019
    2019
    Citations: 4
  • High-Resolution Floating Solar PV Data
    M Matam, RR Hernandez, B Sekulic, AE Cagle, D Jordan, D Chasar, ...
    DOE Open Energy Data Initiative (OEDI); University of Central Florida … , 2022
    2022
    Citations: 3
  • Simulated Impact of Shortened Strings in Commercial and Utility-Scale Photovoltaic Arrays
    RM Smith, M Matam, H Seigneur
    Energies 16 (21), 7222 , 2023
    2023
    Citations: 2
  • An Algorithm for Filtering the Time-series IV curves of a PV plant
    M Matam, H Seigneur
    2021 IEEE 48th Photovoltaic Specialists Conference (PVSC), 0147-0149 , 2021
    2021
    Citations: 2
  • Quantifying and Valuing Fundamental Characteristics and Benefits of Floating PV Systems
    CMC Kettles, M Matam, D Chasar, RR Hernandez, B Sekulic, AE Cagle, ...
    Univ. of Central Florida, Orlando, FL (United States) , 2024
    2024
    Citations: 1