Faculty Publications
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Item Modified Current Control for Tracking Global Peak Under Fast Changing Partial Shading Conditions(Institute of Electrical and Electronics Engineers Inc., 2022) P, P.; Vignesh Kumar, V.; Balasubramanian, B.; Ramana, V.The power - voltage (P-V) characteristics of photovoltaic (PV) systems exhibit multiple power peaks under partially shaded conditions. Several global maximum power point tracking (GMPPT) algorithms in the literature recognize the irradiance change, only after the convergence of operating point to global peak, or use additional hardware to call GMPPT subroutine at definite time intervals to detect any insolation change, and thus track the global peak. However, during fast changing partial shading conditions, these methods are less effective, as they do not detect any irradiance change during the tracking phase of any shading pattern. This paper proposes a novel modified current control approach that uses current as a parameter to detect the insolation change during the tracking phase and track the global peak under fast changing partial shading conditions without any additional hardware. The proposed technique improves the tracking efficiency by as much as 39%, thus proving to be effective under fast-changing partial shading conditions. The superior tracking performance of the proposed algorithm over the existing techniques in terms of its tracking efficiency, dynamic tracking capability, tracking speed, and convergence to the global peak is demonstrated with extensive simulations using MATLAB/Simulink and experimental results. © 1986-2012 IEEE.Item A Novel Algorithm Based on Voltage and Current Perturbation to Track Global Peak Under Partial Shading Conditions(Institute of Electrical and Electronics Engineers Inc., 2022) P, P.; Vignesh Kumar, V.; Koothu Kesavan, K.K.; Balasubramanian, B.Under partial shading conditions, photovoltaic (PV) systems exhibit multiple peaks in their power-voltage (P-V) characteristics. It is essential to extract maximum energy from the PV system. The global maximum power point tracking (GMPPT) algorithms presented in the literature, track the global peak using different methods. It is imperative to have minimal convergence time for GMPPT process. This paper proposes a novel algorithm to track the global peak using voltage and current perturbation. The new GMPPT algorithm operates in a current perturbation or voltage perturbation mode, based on the value of a control variable. In either mode, the proposed technique generates reference current or reference voltage, for navigating the operating point to GMPP location. The proposed algorithm is compared with two GMPPT algorithms, namely, modified maximum power trapezium (M-MPT) and high-performance GMPPT algorithms. The simulation studies are performed in MATLAB and is validated using a laboratory prototype, with dSPACE 1202 MicroLabBox controller for implementing GMPPT methods. Simulation and experimental results show that the new technique exhibits superior performance in terms of tracking time. Also, the energy efficiency is improved by 40% while using the proposed GMPPT algorithm for the irradiance profiles considered in this paper compared to the other two techniques. © 1986-2012 IEEE.Item Design and implementation of seven-level inverter for grid-tied photovoltaic systems(Taylor and Francis Ltd., 2025) Maheswari, G.; Manjunatha Sharma, K.M.; P, P.Multi-level inverters without transformer coupling are growingly popular for solar uses because of their compact design, minimised voltage stress, and improved efficiency. In this paper, the proposed novel triple-boost 7-level inverter is optimised for seamless integration with the grid. The proposed inverter employs self-regulating switched-capacitors to achieve a threefold voltage amplification, effectively eliminating the need for an independent boost converter stage. This architecture benefits low-voltage PV systems by improving efficiency, reducing cost, and ensuring superior performance. Moreover, the 7-level inverter adopts a common-ground topology, effectively mitigating leakage currents in PV system applications. The paper elaborates on the operational modes of the proposed inverter and the design of a current controller tailored for a grid-tied PV-based seven-level inverter. Additionally, simulation and experimental validation are conducted utilising hardware-in-the-loop (HIL) methods to evaluate system performance. Finally, a comprehensive comparative analysis is presented between the proposed seven-level inverter and existing seven-level inverters, highlighting the advantages of the proposed inverter design. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item A Novel Seven-Level Triple-Boost Inverter for Grid-Integrated Photovoltaic Systems(Springer, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; P, P.Transformer-less switched-capacitor-based multilevel inverters (TL-SCMLIs) are increasingly preferred for photovoltaic (PV) applications due to their voltage boosting capability, high efficiency, reduced dv/dt stress, and lower cost. However, existing SC-based multi-level inverters often require more components, suffer from leakage currents, have lower boost gain capability, have higher PU total standing voltage, and exhibit lower efficiency. To address these challenges, this paper proposes a novel seven-level switched-capacitor (SC)-based TL-MLI with higher voltage boosting gain and a common ground (CG) configuration for improved performance in grid-tied PV applications. A proportional-integral (PI) controller is designed for the grid-tied seven-level PV inverter, and its performance is evaluated through simulation studies and hardware-in-the-loop (HIL) experimental verification. Finally, a detailed comparative analysis with existing multi-level inverters highlights the proposed seven-level inverter’s advantages, including leakage current reduction, high boost gain, lower cost, lower PU total standing voltage, lower voltage stress, lower peak inverse voltage, and improved efficiency. The total harmonic distortion (THD) of the grid current is less than 5% for the proposed grid-tied seven-level inverter. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2025.