Browsing by Author "Kulkarni, P.S."

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    A comparison of seven-level inverter topologies for multilevel DC-AC power conversion
    (Institute of Electrical and Electronics Engineers Inc., 2014) Salodkar, P.; Sandeep, N.; Kulkarni, P.S.; Yaragatti, R.Y.
    Multilevel inverter (MLI) performance is high compared to the conventional two level inverters since they offer high power capability, associated with lower output harmonics and lower commutation losses. However the main drawback of MLI is their increased number of power devices, passive components, complex pulse width modulation control and balancing of capacitor voltages. In this paper the most popular topologies like diode-clamped inverter (neutral-point clamped), cascaded multicell with separate dc sources, and transistor clamped H-Bridge inverter are discussed. A simplified multilevel inverter (Switched Transistor MLI) is proposed and its performance is compared with the above said topologies. Component count and the % total harmonic distortion (THD) of the output voltage are considered as the indexes of the comparative performance. The operating principle of each topology, the most relevant modulation method of all the topologies and the detailed analysis of the proposed Switched Transistor MLI is included. The selection of topology and control techniques depends and varies according to power demands of inverter. Simulation study of all the topologies considered is carried out on MATLAB/SIMULINK platform and the performance of the proposed topology is verified experimentally by the tests performed on a scaled laboratory prototype. © 2014 IEEE.
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    A single-stage active damped LCL-filter-based grid-connected photovoltaic inverter with maximum power point tracking
    (Institute of Electrical and Electronics Engineers Inc., 2015) Sandeep, N.; Kulkarni, P.S.; Yaragatti, R.Y.
    In this paper, a simple single-phase grid-connected photovoltaic (PV) inverter topology consisting of a three-level inverter, an LCL filter, and a new current feedback method for active damping is considered. A dynamically rapid method is used for tracking the maximum power point (MPP) of photovoltaic arrays, known as ripple correlation control. The algorithm uses the current and voltage low-frequency oscillations as the perturbation signals, which are introduced in the output of PV array due to the sinusoidal power being injected into the single-phase utility grid, to enable operation at MPP. The capacitor of the conventional LCL filter is split into two parts and the current flowing between these two parts is used as the feedback for regulation of grid current being injected. By doing so the V - I transfer function of the grid connected inverter system degrades to first-order one from third order function. Due to which, wide control-loop bandwidth can be achieved with a large proportional control-loop gain ensuring good stability. Proportional-resonant (PR) current controller is suggested to provide power to the line with unity power factor and the PV inverter offers much less total harmonic distortion. The entire system has been numerically simulated in MATLAB/SIMULINK platform and the performance results are presented for variation in insolation levels and grid voltage profile showing the effectiveness of the proposed system. © 2014 IEEE.
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    Asymmetric H-Bridge Single-Phase Seven-Level Inverter Topology with Proportional Resonant Controller
    (Taylor and Francis Ltd, 2019) Salodkar, P.A.; Kulkarni, P.S.; Waghmare, M.A.; Chaturvedi, P.C.; Sandeep, N.
    This paper presents an asymmetrical H-bridge single-phase seven-level inverter topology with modified gating scheme for reducing the number of high-frequency switches. Due to shortcomings like steady-state error and problems in removing low-order harmonics associated with proportional integral controller, proportional resonant controller is used for grid-connected converter current control. A practical application of proportional resonant current controller is developed using a low-cost dsPIC33EP256MC202 microcontroller to keep the current injected in to the grid. The validity of proposed inverter and control scheme is verified through simulation and implemented for low-voltage laboratory prototype. © 2017, © 2017 IETE.
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    A comparison of seven-level inverter topologies for multilevel DC-AC power conversion
    (2014) Salodkar, P.; Sandeep, N.; Kulkarni, P.S.; Udaykumar, R.Y.
    Multilevel inverter (MLI) performance is high compared to the conventional two level inverters since they offer high power capability, associated with lower output harmonics and lower commutation losses. However the main drawback of MLI is their increased number of power devices, passive components, complex pulse width modulation control and balancing of capacitor voltages. In this paper the most popular topologies like diode-clamped inverter (neutral-point clamped), cascaded multicell with separate dc sources, and transistor clamped H-Bridge inverter are discussed. A simplified multilevel inverter (Switched Transistor MLI) is proposed and its performance is compared with the above said topologies. Component count and the % total harmonic distortion (THD) of the output voltage are considered as the indexes of the comparative performance. The operating principle of each topology, the most relevant modulation method of all the topologies and the detailed analysis of the proposed Switched Transistor MLI is included. The selection of topology and control techniques depends and varies according to power demands of inverter. Simulation study of all the topologies considered is carried out on MATLAB/SIMULINK platform and the performance of the proposed topology is verified experimentally by the tests performed on a scaled laboratory prototype. � 2014 IEEE.
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    Experimental investigations of a low heat rejection (LHR) engine powered with Mahua oil methyl ester (MOME) with exhaust gas recirculation (EGR)
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Kulkarni, P.S.; Godiganur, G.; Ramesh, M.R.; Banapurmath Nagaraj, N.R.; Khandal, S.V.
    Continued effort has been made by several researchers to reduce the dependency on fossil fuels by using suitable alternative and renewable fuels such as biodiesels for energy harvesting and vehicular applications. Alternative fuels can partially or totally replace fossil fuels in diesel engine applications and address tailpipe emissions as well, which lead to global warming. Performance of compression ignition (CI) engines fueled with biodiesel can be further improved with low heat rejection engine facility by suitably utilizing the heat rejected from the engine and thereby improving the thermal efficiency. Present work combustion surfaces of piston, valves and cylinder head were coated with ceramic material, making the engine fully adiabatic, also known as a low heat rejection (LHR) engine. Experiments were conducted on an LHR engine using diesel and Mahua oil methyl ester (MOME) to determine its performance with and without exhaust gas recirculation (EGR). An attempt has been made to compare the performance and emissions characteristics of a CI engine operated on MOME with and without ceramic coating, and the effect of an EGR system developed in-house. EGR was varied from 0 to 20% in steps of 5%. The LHR engine yielded increased brake thermal efficiency (BTE), reduced emissions of smoke, HC[Hydro Carbon] and CO, and increased NOx with MOME when compared to an uncoated engine. As EGR rate increased the BTE and NOx were slightly reduced whereas the HC, CO and smoke were increased. At 10% EGR, 25.96% BTE, 59 HSU smoke, 46 ppm HC, 0.163% volume CO and 1048 ppm NOx were reported. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.
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    A single-stage active damped LCL-filter-based grid-connected photovoltaic inverter with maximum power point tracking
    (2015) Sandeep, N.; Kulkarni, P.S.; Udaykumar, R.Y.
    In this paper, a simple single-phase grid-connected photovoltaic (PV) inverter topology consisting of a three-level inverter, an LCL filter, and a new current feedback method for active damping is considered. A dynamically rapid method is used for tracking the maximum power point (MPP) of photovoltaic arrays, known as ripple correlation control. The algorithm uses the current and voltage low-frequency oscillations as the perturbation signals, which are introduced in the output of PV array due to the sinusoidal power being injected into the single-phase utility grid, to enable operation at MPP. The capacitor of the conventional LCL filter is split into two parts and the current flowing between these two parts is used as the feedback for regulation of grid current being injected. By doing so the V - I transfer function of the grid connected inverter system degrades to first-order one from third order function. Due to which, wide control-loop bandwidth can be achieved with a large proportional control-loop gain ensuring good stability. Proportional-resonant (PR) current controller is suggested to provide power to the line with unity power factor and the PV inverter offers much less total harmonic distortion. The entire system has been numerically simulated in MATLAB/SIMULINK platform and the performance results are presented for variation in insolation levels and grid voltage profile showing the effectiveness of the proposed system. � 2014 IEEE.