Faculty Publications
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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 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 Modified Current Control for Tracking Global Peak Under Fast Changing Partial Shading Conditions(Institute of Electrical and Electronics Engineers Inc., 2022) P, P.; Vignesh Kumar, V.; Balasubramanian, B.; Ramana, V.The power - voltage (P-V) characteristics of photovoltaic (PV) systems exhibit multiple power peaks under partially shaded conditions. Several global maximum power point tracking (GMPPT) algorithms in the literature recognize the irradiance change, only after the convergence of operating point to global peak, or use additional hardware to call GMPPT subroutine at definite time intervals to detect any insolation change, and thus track the global peak. However, during fast changing partial shading conditions, these methods are less effective, as they do not detect any irradiance change during the tracking phase of any shading pattern. This paper proposes a novel modified current control approach that uses current as a parameter to detect the insolation change during the tracking phase and track the global peak under fast changing partial shading conditions without any additional hardware. The proposed technique improves the tracking efficiency by as much as 39%, thus proving to be effective under fast-changing partial shading conditions. The superior tracking performance of the proposed algorithm over the existing techniques in terms of its tracking efficiency, dynamic tracking capability, tracking speed, and convergence to the global peak is demonstrated with extensive simulations using MATLAB/Simulink and experimental results. © 1986-2012 IEEE.Item A Novel Algorithm Based on Voltage and Current Perturbation to Track Global Peak Under Partial Shading Conditions(Institute of Electrical and Electronics Engineers Inc., 2022) P, P.; Vignesh Kumar, V.; Koothu Kesavan, K.K.; Balasubramanian, B.Under partial shading conditions, photovoltaic (PV) systems exhibit multiple peaks in their power-voltage (P-V) characteristics. It is essential to extract maximum energy from the PV system. The global maximum power point tracking (GMPPT) algorithms presented in the literature, track the global peak using different methods. It is imperative to have minimal convergence time for GMPPT process. This paper proposes a novel algorithm to track the global peak using voltage and current perturbation. The new GMPPT algorithm operates in a current perturbation or voltage perturbation mode, based on the value of a control variable. In either mode, the proposed technique generates reference current or reference voltage, for navigating the operating point to GMPP location. The proposed algorithm is compared with two GMPPT algorithms, namely, modified maximum power trapezium (M-MPT) and high-performance GMPPT algorithms. The simulation studies are performed in MATLAB and is validated using a laboratory prototype, with dSPACE 1202 MicroLabBox controller for implementing GMPPT methods. Simulation and experimental results show that the new technique exhibits superior performance in terms of tracking time. Also, the energy efficiency is improved by 40% while using the proposed GMPPT algorithm for the irradiance profiles considered in this paper compared to the other two techniques. © 1986-2012 IEEE.Item Development of Small Signal Model and Stability Analysis of PV-Grid Integration System for EV Charging Application(Institute of Electrical and Electronics Engineers Inc., 2024) Kanimozhi, K.; Koothu Kesavan, K.K.; Nagendrappa, N.; Balasubramanian, B.In this article, grid interactive photovoltaic (PV) system is designed for an electric vehicle (EV) charging application, and the stability of the system is analyzed. The small signal model for the system is derived by averaging and linearizing the state space equations, and the condition for stable operation of PV-integrated charger system is identified from the transfer functions. The proposed charger system implements a coordinated control between the converters to maintain a power balance between the sources and load. System stability is examined using root-locus plots and in addition, the controller is designed to improve the overall stability and reliability of the system. The proposed method provides a general framework for modeling EV charging systems which also details the importance of deriving the model with multiple energy sources. Further, proposed topology has bidirectional capability, which transfers excess PV power to the grid during off-charging hours. The efficacy of the proposed method is verified using the MATLAB Simulink environment for the different scenarios, i.e., variation in the irradiation and disturbances in the grid voltage. The experimental study is conducted on a 1.5-kW laboratory prototype using a low-cost digital signal processing controller (launchpad TMS320F28027F) and the measured results authenticate the simulation findings. © 2020 IEEE.Item Implementation of Coordinated Control and Power Flow Management Strategy for a Solar Powered EV Charging System(Institute of Electrical and Electronics Engineers Inc., 2025) Kanimozhi, K.; Koothu Kesavan, P.; Nagendrappa, N.; Balasubramanian, B.This paper introduces a novel coordinated control and power flow management strategy (CC-PFMS) for a solar integrated electric vehicle (EV) charging system. The CC-PFMS is designed to have inherent power balance capability under various operating modes with multiple energy resources. Further, it will facilitate the direction of power flow from grid to battery or vice versa irrespective of the charger system dynamics. The main advantage of proposed strategy is to identify different conditions such as change in solar irradiance, vehicle availability and battery charging/discharging state and ensure the stable operation. The veracity of the new approach is tested on 1.5 kW charger system having photovoltaic (PV) source integrated with utility grid. The performance of CC-PFMS under various operating modes viz. grid to vehicle (G2V), vehicle to grid (V2G), PV to vehicle (PV2V), PV to grid (PV2G), G2V+PV2V, V2G+PV2G and PV2V+PV2G is substantiated through extensive MATLAB simulations. The experiments were also performed in the laboratory prototype to confirm the simulation findings and recorded results were presented. © 1975-2011 IEEE.