Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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Item Modeling of photovoltaic system for uniform and non-uniform irradiance: A critical review(Elsevier Ltd, 2015) Jena, D.; Ramana, V.V.A critical review on various modeling approaches of photovoltaic array both under uniform and non-uniform irradiance is presented in this paper. The main approaches that have been deliberated are based on the variation of analytical methods, classical optimization techniques and soft computing techniques. The review has been taken from papers published up to 2015. In this paper a detailed description and classifications of modeling techniques for both uniform and non-uniform irradiance conditions are presented. Modeling of PV systems under uniform irradiance is classified into non-iterative methods, iterative methods, artificial intelligence based methods and dynamic models. Under non-uniform irradiance, they are classified into non-iterative methods, iterative methods and artificial intelligence based methods. It is envisaged that this paper can serve as valuable information for researchers to work on photovoltaic array modeling under partial shaded condition. © 2015 Elsevier Ltd. All rights reserved.Item An accurate modeling of photovoltaic system for uniform and non-uniform irradiance(International Journal of Renewable Energy Research ijrereditor@gmail.com, 2015) Ramana, V.V.; Jena, D.Efficient modeling and simulation of photovoltaic (PV) systems has become more important due to the wide integration of solar energy in modern power systems. The equations describing the PV systems are transcendental nonlinear in nature, this results a slow and inefficient simulations for long-term analysis. This paper proposes a modified approach of modeling photovoltaic array for uniform and non-uniform irradiance condition. Initially for uniform irradiance condition single diode model is used as equivalent circuit. A method based on adaptively varying the value of series resistance is proposed to find the equivalent circuit parameters. The proposed model is simulated using MATLAB and results are validated using the experimental results obtained from the datasheet values and other models in the literature. The model is extended for non-uniform irradiance and the results are validated. The proposed methodology found to have advantage over the other conventional methods in terms of accuracy and less simulation time.Item An accurate modeling of different types of photovoltaic modules using experimental data(International Journal of Renewable Energy Research, 2016) Ramana, V.V.; Jena, D.; Gaonkar, D.N.In this paper an approach to model different types of PV modules using single diode model is presented. The proposed method utilizes the characteristics of diode ideality factor, shunt resistance and series resistance independently for developing accurate solar PV model. Apart from this, the proposed model utilizes experimental values obtained from the solar array simulator for implementing the proposed approach. The procedure mainly focuses on developing an accurate method for thin film solar modules using a simplified approach. The model is implemented in MATLAB and is validated with existing model and experimental values obtained from solar array simulator.Item Global Peak Tracking of Photovoltaic Array under Mismatching Conditions Using Current Control(Institute of Electrical and Electronics Engineers Inc., 2019) Ramana, V.V.; Mudlapur, M.; Damodaran, R.; Balasubramanian, B.; Mishra, S.Characteristics of photovoltaic arrays exhibit multiple peaks under mismatching conditions. In order to harness maximum energy, it is imperative to track the global maximum power point. A novel global peak tracking algorithm is proposed using current control in this paper. The proposed method operates in the backward phase and forward phase to track the global peak. The objective of the proposed algorithm is to track the global maximum accurately with minimum tracking time. The enhanced performance of the proposed algorithm is verified using simulations by comparing it with an existing method. Experimental validation is done using a solar array simulator, boost converter, resistive load, and dSPACE controller. Experimental results are in close agreement with simulation. The proposed algorithm is intended to track the global peak of a PV string that contains a group of modules. © 1986-2012 IEEE.Item Effect of Partial Shading on PV Fed Induction Motor Water Pumping Systems(Institute of Electrical and Electronics Engineers Inc., 2019) Mudlapur, M.; Ramana, V.V.; Damodaran, R.; Balasubramanian, B.; Mishra, S.Partial shading is one of the certain conditions in photovoltaic (PV) power plants. Often the panels get partially shaded due to soiling, clouds, and trees. The effect of shading is of high concern and importance especially in applications such as water pumps due to agricultural environments in which they are employed in. However, the research focus on PV fed pumps till date has been restricted to only uniform shading conditions. Unlike uniform shading conditions during maximum power tracking, where the panel voltage remains almost constant for an entire range of irradiance, partial shading offer conditions such as highly variable panel voltage and transitions of intermediate DC-DC power converter from continuous conduction mode to discontinuous conduction mode. These effects severely affect the performance of the power converter and, therefore, the power output of the pump. This paper presents a study on the effects caused by partial shading conditions on pumps through simulations and verified by experimentations. The simulation and experimental results are found to be in good agreement with each other. This research thus helps in understanding the detrimental effects caused by partial shading conditions and thus serves as a reference tool for practitioners who wish to study PV fed pumps. © 1986-2012 IEEE.Item An Iterative Analytical Solution for Calculating Maximum Power Point in Photovoltaic Systems under Partial Shading Conditions(Institute of Electrical and Electronics Engineers Inc., 2019) Mudlapur, M.; Ramana, V.V.; Damodaran, R.; Balasubramanian, B.Detection of maximum power point (MPP) is one of the most sought-after topics in the field of photovoltaic systems. There are many approaches to detecting MPP, amongst these are analytical methods. Analytical methods use mathematical functions to solve the given problem and therefore are one of the dominant strategies. However, their applications to detect MPP have been limited to study only uniform shading conditions. The use of analytical methods to detect MPP for more challenging cases like partial shading conditions is yet to be investigated. In this brief, an analytical solution to identify MPP under partial shading conditions is proposed. Equations describing photovoltaic panels and MPP conditions are derived by applying fundamental circuit laws. The derived equations are non-linear and can be solved using numerical techniques available in most of the simulation packages. The proposed model can theoretically detect the MPP amongst 'N' peaks. The results from the simulation are verified by conducting experimentation with standard algorithms available in the literature. The results from simulation and experimentation are found to agree with each other. © 2004-2012 IEEE.Item Small Signal Model for PV Fed Boost Converter in Continuous and Discontinuous Conduction Modes(Institute of Electrical and Electronics Engineers Inc., 2019) Mudlapur, M.; Ramana, V.V.; Damodaran, R.; Balasubramanian, B.Small signal models are of high importance in power electronic systems which exhibit highly non-linear properties. They provide access to stability and help in tuning controllers. Small signal models for many power electronic converters are seen in the literature. However, specific applications like photovoltaic systems demand the addition of a capacitor at the terminals of photovoltaic (PV) panel. Since this capacitor is connected between the PV panel terminals and the input of power converter, it is termed as input capacitor. The effect of the addition of input capacitor on system stability has not been addressed yet. In this brief, we derive the small signal models for PV fed boost converter operating in both continuous conduction mode (CCM) and discontinuous conduction modes (DCM) of operation. The load is assumed as purely resistive; however, the analysis holds good for any practical loads. It is observed that in both CCM and DCM the stability of the maximum power point tracking (MPPT) system is independent of the input capacitance. It is also shown that the MPPT system is open loop stable for all operating conditions. The studied models are further validated with the experimental setup. © 2004-2012 IEEE.Item A Novel AC Current Sensorless Hysteresis Control for Grid-Tie Inverters(Institute of Electrical and Electronics Engineers Inc., 2020) Damodaran, R.; Mudlapur, A.; Ramana, V.V.; Balasubramanian, B.; Mishra, S.Amongst the modulation techniques used for grid-Tie inverters (GTIs), hysteresis current control (HCC) facilitates simple, stable and rugged control with improved dynamic response. However the variable switching frequency of HCC demands high precision AC current sensors (CS) which introduce noise in the power circuit in addition to measurement noise and delay. Therefore, this brief presents a hysteresis current control without AC current sensor based on switching instant computation for a two-level GTI. The proposed control strategy uses the DC link and instantaneous grid voltages to calculate the switching instants. The conventional methods of calculating switching instant of HCC can result in tracking errors. Hence the computations are modified in the proposed algorithm considering the effects of non-linearity in error current and dynamic variations due to supply and load changes. A single-phase GTI is simulated with the proposed control and the results are verified experimentally. The proposed method is observed to considerably reduce the computational time, DC shift and total harmonic distortion compared to the commonly used sensorless current control. © 2004-2012 IEEE.