Faculty Publications
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Publications by NITK Faculty
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Item A Global Maximum Power Point Tracking Technique of Partially Shaded Photovoltaic Systems for Constant Voltage Applications(Institute of Electrical and Electronics Engineers Inc., 2019) Goud, J.S.; Kalpana, R.; Singh, B.; Kumar, S.The P-V characteristics of photovoltaic (PV) array exhibit several maximum power points (MPP) during non-uniform insolation (i.e., during partial shading) conditions; there exists only one global MPP (GMPP), whereas others are referred to local MPP. This paper presents a technique to track the GMPP for the constant voltage or battery loads during partial shading conditions using a single sensor connected to the battery terminals. The proposed method introduces fast and efficient scanning based method, i.e., scanning Ibatt-D curve of power electronic interface at selective duty cycles to recognize the kind of the solar shading pattern (i.e., kind of P-V curve) on PV array and to find the GMPP neighborhood. Moreover, the proposed method overcomes the drawbacks of existing methods such as low convergence speed, increased number of sensors, and heavy computational complexity. The proposed GMPPT method is simulated in MATLAB/Simulink and validated through test results on a prototype for various non-uniform insolation conditions. The results have shown that this paper tracks the GMPP with best tracking efficiency and fast tracking speed. Further, the proposed method is compared with two P-V curve scanning based GMPPT methods and one global optimization based artificial bee colony method. © 2018 IEEE.Item An Online Method of Estimating State of Health of a Li-Ion Battery(Institute of Electrical and Electronics Engineers Inc., 2021) Goud, J.S.; Kalpana, R.; Singh, B.Li-ion batteries are playing a crucial role in the fields of renewable energy systems and electric vehicles. The reliability of these systems depends on a battery management system (BMS) which monitors the state of charge (SoC) and state of health (SoH) effectively. Knowing the SoH of a battery in advance enhances the system reliability. This article proposes an accurate online estimation of SoH of a Li-ion battery integrated in solar photovoltaic system (SPV) applications. The proposed method uses the modified coulomb counting method to estimate the SoH of a battery. The proposed SoH estimation method is simulated in MATLAB/Simulink by considering the aging factors such as temperature, charge/discharge rates and depth of discharge. Moreover, the proposed method is validated using an experimental prototype and the results are found to be satisfactory. © 1986-2012 IEEE.Item A Power Quality Enhanced Push-Pull Converter-Based Two-Stage Onboard Charger for Electric Vehicle Applications(Institute of Electrical and Electronics Engineers Inc., 2025) Suprabha Padiyar, U.S.; Kalpana, R.This paper presents an efficient two-stage onboard charger (OBC) using AC-DC converters with improved power quality for electric vehicle (EV) applications. The first stage comprises a diode bridge rectifier (DBR) without an input AC filter and a front-end boost converter (FBC) as a power factor correction (PFC) circuit, stabilizing the output voltage for efficient power transfer. The boost inductor current control is facilitated using a phase-locked loop to achieve input current wave shaping. This FBC drives the second-stage back-end push-pull converter (BPPC) operating in buck mode to ensure the battery is charging in constant current (CC) control mode. The push-pull converter demands its inductor current to be continuous due to the CC mode of battery charging. A detailed analysis of the power converters is conducted through simulations performed using the MathWorks SIMULINK software. Furthermore, a scaled-down hardware prototype has been developed, utilizing a dSPACE 1202 controller, to evaluate the effectiveness of the charger for a 48 V, 100 Ah battery. The test results demonstrate satisfactory performance and compliance with the IEC 61000-3-2 standard. This design effectively maintains input AC power quality during battery charging, highlighting its potential for enhancing EV charging infrastructure. © 2025 The Authors.Item An Integrated EV Battery Charger With Three-Level Boost PFC Converter and H5-Bridge Based Bidirectional DO-CLL Series Resonant Converter for Wide Battery Voltage Range(Institute of Electrical and Electronics Engineers Inc., 2025) Vinusha, B.; Kalpana, R.; Kishan, D.This article proposes an efficient two-stage ac–dc converter for off-board electric vehicle charging applications over a wide range of battery voltages. The proposed charger integrates a three-phase three-level boost power factor correction (TL-BPFC) converter with a bidirectional dual-output CLL (DO-CLL) series resonant converter. In the ac–dc conversion stage, three switches are controlled using a hysteresis technique to enhance input power quality. The second stage, responsible for dc–dc conversion, incorporates an H5-bridge on the primary side and a voltage doubler circuit on the secondary side, providing decoupled outputs through two high-frequency transformers (HFTs) connected to resonant tanks. This configuration allows flexible adjustment of the resonant tank inputs, which can operate in full-bridge (FB), half-bridge (HB), or inactive (IA) modes. This design provides a key advantage of a wide voltage range during forward and reverse operation using reconfigurable H5 bridge. Additionally, the switches in the DO-CLL achieve zero-voltage switching (ZVS) during turn-on, and the identical HFTs minimize the cross-coupling effect, to enhance the efficiency. A scaled-down laboratory prototype of the off-board EV charger is developed to provide two distinct outputs of 400 V and 200 V, achieving an overall efficiency of 97.6%. © 1982-2012 IEEE.