Faculty Publications
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Item Cumulant-based correlated probabilistic load flow considering photovoltaic generation and electric vehicle charging demand(Higher Education Press Limited Company, 2017) Bhat, N.G.; Prusty, B.R.; Jena, D.This paper applies a cumulant-based analytical method for probabilistic load flow (PLF) assessment in transmission and distribution systems. The uncertainties pertaining to photovoltaic generations and aggregate bus load powers are probabilistically modeled in the case of transmission systems. In the case of distribution systems, the uncertainties pertaining to plug-in hybrid electric vehicle and battery electric vehicle charging demands in residential community as well as charging stations are probabilistically modeled. The probability distributions of the result variables (bus voltages and branch power flows) pertaining to these inputs are accurately established. The multiple input correlation cases are incorporated. Simultaneously, the performance of the proposed method is demonstrated on a modified Ward-Hale 6-bus system and an IEEE 14-bus transmission system as well as on a modified IEEE 69-bus radial and an IEEE 33-bus mesh distribution system. The results of the proposed method are compared with that of Monte-Carlo simulation. © 2017, Higher Education Press and Springer-Verlag Berlin Heidelberg.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 The high energy supercapacitor from rGO/Ni(OH)2/PANI nanocomposite with methane sulfonic acid as dopant(Academic Press Inc. apjcs@harcourt.com, 2019) Viswanathan, A.; Nityananda Shetty, A.N.The low energy densities of supercapacitors limit their utilization as energy storage and energy conversion devices. To overcome this limitation, here we present a ternary nanocomposite of reduced graphene oxide (rGO)/nickel hydroxide (Ni(OH)2/polyaniline (PANI), with methane sulfonic acid as dopant, having weight percentages of 14%:14%:72% (G14NP), respectively, as an electrode material for supercapacitor. With 1 M sulfuric acid (H2SO4) as the electrolyte, the supercapacitor yields a high energy density of 120.48 W h kg?1, comparable with those of Li-ion batteries. The G14NP also exhibits good electrochemical performance with a specific capacitance of 602.40 F g?1 and a power density of 2584.83 W kg?1, at a current density of 1 A g?1. The G14NP also exhibits a promising stability of its electrochemical performances even after 16,500 cycles at a potential scan of 400 mV s?1. Remarkably, the composite performs exceptionally well at a potential window available in an aqueous electrolyte. The sustainability to high current loading while charging and its power backup application is satisfactorily demonstrated, by charging with a commercial 9 V battery. © 2019 Elsevier Inc.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 Numerical investigation of cooling performance of a novel air-cooled thermal management system for cylindrical Li-ion battery module(Elsevier Ltd, 2021) Kausthubharam, n.; Koorata, P.K.; Chandrasekaran, N.Batteries strongly influence the performance of electric vehicles. Therefore it is crucial to develop a battery thermal system that is highly efficient in removing the battery pack's heat during its operation. In this paper, a numerical analysis of a lumped thermal model coupled with fluid flow equations is employed to investigate the novel air-cooled battery thermal management system (BTMS). The cooling efficiency of the proposed battery thermal system with commercial thermal interface material (3M™) is investigated by comparing it with a standard battery pack at different discharge rates. The proposed solution offers a 25% reduction in peak temperature when compared to the standard one. The thickness of the thermal interface material is found to have an insignificant impact on the battery pack's thermal performance. Introducing forced air-cooling in the battery pack reduced the maximum temperature considerably but increased the temperature difference compared to the battery pack without forced convection. Then the effect of various structural and operational parameters on the performance of the BTMS is investigated. Moving the air inlet-outlet boundaries to a central location increased the uniformity of temperature distribution in the battery pack. Although the increase in the inlet airflow velocity reduces the maximum temperature, it comes at the cost of an increase in temperature difference and power consumption. It is further observed that a reduction in ambient temperature reduces the peak temperature and makes the temperature distribution in the battery pack more homogeneous. The discharge voltage curves indicate a slight reduction in cell potential as a reducing function of temperature. © 2021 Elsevier LtdItem A novel nine-level boost inverter with a low component count for electric vehicle applications(John Wiley and Sons Ltd, 2021) Shiva Naik, B.S.; Yellasiri, Y.; Aditya, K.; Nageswar Rao, B.N.In electric vehicles (EVs), considerable battery cells are cascaded in series for motor driving to improve the output voltage. The series combination of battery cells causes challenges like isolation of faulty cells, voltage unbalance, and slow charge equalization. Therefore, state-of-charge (SOC) and voltage equalization circuits are often used in industries to protect the battery cells. A nine-level inverter circuit with a double voltage boost is proposed to reduce the above issues based on the switch-capacitor (SC) principle. Unique features like self-balancing, voltage boosting are attained, which cannot be achieved through traditional inverters. The proposed topology can operate at a wide range of modulation indices ((Formula presented.)) to produce different voltage levels. The absence of a back-end H-bridge in the proposed circuit offers low voltage stress across the semiconductors. The operating principle, capacitor sizing, and modulation approach are presented. Further, experimental tests are conducted at different loading conditions to verify the performance of the proposed circuit. © 2021 John Wiley & Sons Ltd.Item Design and Implementation of Different Drive Topologies for Control of Induction Motor for Electric Vehicle Application(River Publishers, 2022) Husain, M.A.; Rajput, R.; Gupta, M.K.; Tabrez, M.; Ahmad, M.W.; Ilahi Bakhsh, F.I.To improve driving range in Electric vehicles (EV), parallel-series connection of battery cells is a necessity. Supressing the circulating current in the battery board of parallel connected battery strings helps improve the lifespan of the batteries. This study presents a comparison of the requirements of parallel strings of batteries in three different popular topologies for open end winding induction motor (IM) drives in EV. The topologies analyzed are a 3-phase voltage source inverter (VSI), a Dual fed inverter and three single-phase HBridge VSIs. These converters are modulated using Space vector pulse width modulation (SVPWM) as it has better performance compared to Sine PWM. MATLAB-Simulink models are developed for the converter topologies. The simulation results show that the three single-phase inverter topology feeding the drive is the best alternative when compared on the basis of battery requirement and switch loss. Moreover, each H-bridge inverter (in the three single-phase inverter topology) can be used as charger and the problem of circulating current during charging will also be least as compared to other schemes. © 2022 River Publishers.Item Magnetic Coupling Characteristics and Efficiency Analysis of Spiral Magnetic Power Pads for Inductive WPT System(River Publishers, 2022) Kishan, D.The inductive wireless power transfer system (IWPT) for electric vehicle battery charging works based on the principle of mutual induction (MI). The amount of power transfer from source to vehicle battery be contingent on the mutual inductance (MI) within the inductively coupled pads. This mutual inductance depends on the type of the inductive power pads, the distance among them, their positioning etc. This paper develops and study the inductive coupling characteristics of identical spiral circular and square inductive power pads. The coupling characteristics at various misalignments with different vertical distance between the coils is presented. In this work, the inductive power pads without using ferrite bars, and with ferrite bars are considered. The coupling characteristics of the spiral circular and square are computed using FEM simulations and validated with experimental results. This paper also investigated the power loss and efficiency analysis of the spiral inductive pads of the resonant IWPT system. © 2022 River Publishers.Item Model predictive controlled three-level bidirectional converter with voltage balancing capability for setting up EV fast charging stations in bipolar DC microgrid(Springer Science and Business Media Deutschland GmbH, 2022) Nisha, K.S.; Gaonkar, D.N.Transportation electrification and charging infrastructure development has to gain momentum in order to go hand-in-hand with the fast advances in the electric vehicle technology. Setting up dc fast charging stations connected to bipolar DC microgrid is a great viable option to utilize the distributed energy resources for transportation electrification. It also helps to eliminate power quality issues in ac grid that may arise due to the unpredictable charging/discharging behaviour of EVs. This paper focuses on model predictive control of a three-level bidirectional dc–dc converter suitable for interconnecting bipolar DC microgrid with dc fast charging stations or battery energy storage. State space analysis is done, and discrete model is developed. Simulation of the proposed system with model predictive control is done in Simulink MATLAB. Real-time hardware in loop performance is tested and verified using Typhoon HIL 402. The proposed converter is able to mitigate the voltage unbalance issues arising in the bipolar DC microgrid and is capable of controlling bidirectional power flow, hence suitable for V2G/G2Voperation. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Operation and control of multiple electric vehicle load profiles in bipolar microgrid with photovoltaic and battery energy systems(Elsevier Ltd, 2023) Nisha, K.S.; Gaonkar, D.N.; Sabhahit, N.S.Charging of electric vehicles is going to be a major electrical load in the near future, as more and more population shift to electric auto-motives from conventional internal combusted engine-powered vehicles. Integration of electric vehicle charging stations (EVCS) might even burden the existing grid to a point of collapse or grid failure. Establishing charging stations interfaced with bipolar DC microgrids along the roads and highways is the most realistic and feasible solution to avoid the overburdening of the existing power system. The bipolar DC microgrid is a far better microgrid structure than the unipolar microgrid structure in many aspects like reliability, flexibility, and controllability. It can provide multiple voltage level interfaces according to the load demands, which is very apt for different charging levels of electric vehicles (EVs). Operation of multiple sources and multiple loads connected to bipolar DC microgrid will affect DC voltage regulation, capacitance-voltage balancing, and overall stable operation of the grid. In order to mitigate these power quality problems arising in multi-node bipolar DC microgrids, a decentralized model predictive control is proposed in this paper. EV charging load profiles are modeled and developed by considering standard driving cycles, state of charge, and power demand of multiple vehicles to study the effect of unpredictable varying EV loads in the bipolar DC microgrid. EVCS thus modeled are connected to solar photovoltaic-battery energy storage fed bipolar DC microgrid with three-level/bipolar converters and analyzed under dynamic conditions for capacitance–voltage unbalance mitigation, voltage regulation, and the stability of operation with model predictive control. Simulation studies are carried out in MATLAB/Simulink to verify the effectiveness of the system. © 2022 Elsevier Ltd
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