Faculty Publications
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Item Numerical Analyses of Single-Phase Pressure Drop and Forced Convective Heat Transfer Coefficient of Water–Ethanol Mixture: An Application in Cooling of HEV Battery Module(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2016) Suhas, B.G.; Sathyabhama, A.The present numerical analyses are related to the cooling of a hybrid electric vehicle (HEV) battery module by water–ethanol mixture. The fluid is passed through a cold plate consisting of two rectangular channels of 0.01 m depth, 0.015 m width, and 0.15 m length. The battery module is represented by a heater placed below the cold plate. The single-phase pressure drop and single-phase heat transfer coefficient for water, water–ethanol mixture of mass fraction of 25%, 50%, and 75%, and ethanol are determined numerically for different heat fluxes of 10, 15, 20, and 25 kW/m2 and different Reynolds numbers 500, 1000, 1500, 2000, and 2500. To solve the Navier–Stokes equation, the pressure correction method was used and to solve the energy equation, the Lax–Wendroff explicit method is used. Numerical results obtained for water are compared with the literature correlations. The friction factor for water deviated by an average of 8.02% from the Lewis and Robertson equation. The Nusselt number for water deviated by 7.35% from the Churchill and Ozoe equation at lower Reynolds number 500 and at higher Reynolds number 2500, Nusselt number deviated by 13.68% from the Stephan equation. The results showed that the heat transfer coefficient increased with an increase in Reynolds number and heat flux. The effect of the increase in Reynolds number is more significant than the increase in heat flux. At higher ethanol mass fraction and higher Reynolds number the heat transfer coefficient increased with heat flux when compared to water. There is no significant decrease in heat transfer coefficient with an increase in ethanol mass fraction. The pressure drop increased and the heat transfer coefficient decreased with an increase in ethanol mass fraction. © 2015 Wiley Periodicals, Inc.Item Design and analysis of dual output flyback converter for standalone PV/battery system(International Journal of Renewable Energy Research, 2017) Sabhahit, N.S.; Gaonkar, D.N.; Naik, A.In this paper, the cost comparison is carried out among flyback, forward and full bridge converters based upon the number of circuit components. The performance assessment in terms of efficiency of the PV array with MPPT controller using flyback and forward converter is detailed. The design and control of Photovoltaic/battery system using a flyback converter for stand-alone applications is presented. A flyback converter is used to get DC output along with an AC output for high frequency applications without employing an inverter. The PV/battery system uses photovoltaic array as the main source of power and a battery as the storage device. The energy input of the PV system is effectively utilized by adopting an MPPT technique and the storage battery is controlled to balance the load requirements using a bi-directional dc-dc converter. This system ensures that the load demand is satisfied under varying solar irradiance conditions and a constant voltage is maintained for different load conditions. The modelling and control strategy of the implemented system is realized in MATLAB/Simulink environment.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 Effect of current density and electrochemical cycling on physical properties of silicon nanowires as anode for lithium ion battery(Elsevier Inc. usjcs@elsevier.com, 2017) Ramesh, R.; H.S., N.Herein, we successfully fabricated vertically aligned silicon nanowires (Si NWs) via an electrochemical etching of n-type (100) silicon at different high current densities. The morphology of the prepared Si NWs was studied using SEM, FFT analysis and WSxM software. From FTIR spectroscopy analysis, the silicon dangling bonds of the as-prepared Si NWs layer have large amount of hydrogen to form weak Si[sbnd]H bonds. The blue shift was observed in Photoluminescence due to decrease in the size of silicon crystallites, the crystallite size in the Si NWs varied from 5.9 nm to 4.8 nm depending on the current density. The contact angle varied from 74.7° to 149.1°. From the wettability studies, the surface nature of the Si NWs was converted from hydrophilic to hydrophobic when the current density increased. The obtained Si NWs were used as an anode in lithium ion cell. The charge capacity of the anode is ~ 3452.47 mAh g? 1 at the first cycle with the coulombic efficiency over 85.8%, and faded to 1134.34 mAh g? 1 with coulombic efficiency over 81.6% after the 12th cycle at a current rate of 1C. Scanning electron microscopy and selected area electron diffraction are performed to study the morphology and crystalline structure of the anode, respectively. The dislocation density decreased from 46.2 × 1015 m? 2 to 0.06 × 1015 m? 2 and the surface area decreased from 1.5 × 103 ?m2 to 0.05 × 103 ?m2 with cycle number increased from 1 to 102 whereas the band gap increased from 2.2 eV to 2.9 eV. The above observations are well correlated. © 2017 Elsevier Inc.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 electroactive ?-phase polyvinylidene fluoride as gel polymer electrolyte for magnesium–ion battery application(Elsevier B.V., 2019) Singh, R.; Janakiraman, S.; Khalifa, M.; Anandhan, S.; Ghosh, S.; Adyam, A.; Biswas, K.The gel polymer electrolytes (GPEs) are currently interesting research area in rechargeable batteries. In the present study, synthesis and characterization of electroactive gel polymer electrolyte (EGPE) for Mg-ion batteries application have been investigated. The bead free electroactive polyvinylidene fluoride (PVDF) with high porosity is achieved by an electrospinning process. The ?-phase of PVDF is polar and electroactive with a high dipole moment. Electroactive ?-phase is confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Field emission scanning electron microscopy (FESEM) study is done to analyze the structure and morphology of the electroactive membrane. The electroactive gel polymer electrolyte is formed by immersing an electroactive PVDF membrane in 0.3 M magnesium perchlorate (MgClO4) and propylene carbonate (PC) solution. The ionic conductivity of electroactive ?-phase PVDF membrane is achieved to be 1.49 mS cm?1 at 30 °C, which is higher than commercial available polypropylene (PP) Celgard. Tortuosity of electroactive gel polymer electrolyte is found to be 1.44. The voltage stability of the EGPE is stable up to a high voltage of 5.0 V against Mg+2/Mg. The total ionic transference number and magnesium ion transference number of EGPE are also investigated to confirm high ionic conductivity. © 2019 Elsevier B.V.Item A high thermally stable polyacrylonitrile (PAN)-based gel polymer electrolyte for rechargeable Mg-ion battery(Springer, 2020) Singh, R.; Janakiraman, S.; Khalifa, M.; Anandhan, S.; Ghosh, S.; Adyam, A.; Biswas, K.The ionic conductivity and thermal stability of the electrolyte-separator system is an essential parameter for improving battery performance and safety. The present work addresses the high thermally stable gel polymer electrolyte (GPE) using polyacrylonitrile (PAN) as a polymer membrane and magnesium perchlorate in propylene carbonate (Mg(ClO4)2-PC) as a liquid electrolyte. The PAN based polymer membrane is prepared by electrospinning process which produces a bead free and uniformly distributed nanofibers. The electrospun PAN based GPE is characterized by different physical and electrochemical techniques like X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, ionic conductivity, linear sweep voltammetry, magnesium ion transference number and electrochemical impedance spectroscopy. The ionic conductivity of PAN is 3.28 mS cm?1, compared to that of PP Celgard is 1.97 × 10–4 mS cm?1 at 30 °C. The electrochemical stability of PAN is 4.6 V and also exhibits excellent interfacial stability with magnesium metal. The results showed that the PAN-based GPE has higher ionic conductivity and thermal stability than the polypropylene (PP) Celgard membrane. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Item 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.
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