Informatics Publishing Limited

J. Divya Navamani ¹, A. Lavanya ¹

Affiliations
1 Electrical Engineering Department, SRM University, IN

Abstract

This paper proposes the method of tracking the maximum power point from a photovoltaic cell or array, even though the performance of PV cell varies with isolation. The output characteristics of PV cell is non-linear, therefore MPPT technique is implemented. A new MPPT algorithm using Modified Adaptive Hill Climbing control algorithm (MAHC). Control parameter of MPPT is switching duty cycle (or) duty ratio (D). The simulation results show that the proposed MPPT control can avoid tracking deviation and result in improved performance in both dynamic response and steady-state.

Keywords

Equivalent Circuit, Modeling, Photovoltaic PV MPPT, MHAC, Simulation.

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J. Divya Navamani ¹, A. Lavanya ¹

Affiliations
1 SRM University, IN

Abstract

Constructing the network and number of Cognitive radio networks have been proposed as a solution to both spectrum inefficiency and spectrum scarcity problems. However, they face to a unique challenge based on the fluctuating nature of heterogeneous spectrum bands as well as the diverse service requirements of various applications. In this paper, a spectrum decision framework is proposed to determine a set of spectrum bands by considering the application requirements as well as the dynamic nature of spectrum bands. To this end, first, each spectrum is characterized by jointly considering primary user activity and spectrum sensing operations. Based on this, a minimum variance based spectrum decision is proposed for real-time applications, which minimizes the capacity variance of the decided spectrum bands subject to the capacity constraints. For best-effort applications, a maximum capacity-based spectrum decision is proposed where spectrum bands are decided to maximize the total network capacity. Moreover, a dynamic resource management scheme is developed to coordinate the spectrum decision adaptively dependent on the time-varying cognitive radio network capacity. Simulation results show that the proposed methods provide efficient bandwidth utilization while satisfying service requirements.

Keywords

Cognitive Radio Networks, Spectrum Decision, Minimum Variance-Based Spectrum Decision, Maximum Capacity-Based Spectrum Decision, Resource Management.

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Divya Navamani ¹, K. Vijayakumar ¹, A. Lavanya ¹

Affiliations
1 EEE Department, SRM University, IN

Abstract

Objective: Small-signal modelling is a widespread analysis practice in power electronic converters which is used to fairly accurate the performance of non-linear devices with linear equations. The order of the dc-dc depends on the non-linear elements of the system. As the number of non-linear element of the converter is high, it’s modelling and control becomes extremely complicated. Thus, there is a need for generalization of such converters by small signal modelling. Traditional modelling schemes using the averaging and small-signal linearization procedures are utilised for the advance modelling of the converters. Method: In this work, the purpose of the switching flow graph (SFG) and the Mason’s gain formula aid the solution of the equations. The duty cycle to output and the input to output transfer functions are obtained. Those transfer function can be used for closed loop examination. Findings: Open loop analysis of the converter is done and the outcomes are verified through simulation. Theoretical and simulation results are shown to prove the accuracy of the developed small signal models. The derived topology is unstable in open loop condition. A prototype is developed to validate the performance of the proposed topology. Improvement: Closed loop analysis can be carried out with any type of controller.

Keywords

Loops, Modelling, Stability, Transfer Function, Voltage Gain.

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J. Divya Navamani ¹, K. Vijayakumar ¹, A. Lavanya ¹

Affiliations
1 EEE Department, SRM University, SRM Nagar, Potheri, Kattankulathur, Kancheepuram - 603203, Tamil Nadu, IN

Abstract

An isolated full-bridge dc-dc converter with voltage doubler (IFBVD) is mainly used in higher power applications. This paper presents the testing and implementation of a digitally controlled Random pulse width modulated isolated full-bridge DC-DC converters with voltage doubler (IFBVD). Different PWM techniques for full-bridge DC/DC converter are investigated. Field Programmable Gate Array (FPGA) is used to obtain different PWM techniques. It is most commonly used in designing PWM Generator for Power Converter Applications. A comprehensive comparison between the various PWM techniques, including current stress, ripple and efficiency, is presented. Simulation is done using Matlab/Simulink. An experimental setup has been provided to validate the theoretical and simulation results using FPGA control. Experimental results of a 0.5kW, 50kHz prototype are presented.

Keywords

DC-DC Converter, FPGA, Phase Shift, Random PWM, Ripples

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Divya Navamani , Rishab Mrinal , A. Lavanya , A. Geetha

Abstract

In this paper, the dynamic analysis of the dc-dc converter is proposed with an educational aid to ease the process in which the study is carried out. This study's primary importance is that it can be added to the curriculum of Master's program in Electrical Engineering. This article mainly focuses on the mathematical modelling of the dc-dc converter with which the dynamic analysis is carried out to regulate the load and line condition. The main problems in the analysis of higher-order dc-dc converter is addressed with techniques available in the literature. A quadratic boost converter with DCL cell is chosen for studying the dynamic analysis with the flow of the technique proposed. The solution to the resolvent matrix of the converter is obtained using Leverrier's algorithm. The higher-order system's transfer function is reduced using the pole clustering technique to ease the controller design. Finally, the PI controller is tuned with Ziegler-Nichols tuning and it is incorporated with the converter using the reduced-order transfer function. The input to output transfer function is analyzed with the step response in MATLAB software and compared with the full order transfer function to validate the reduced-order transfer function. The closed-loop response is also validated both with full order and reduced-order system.

Keywords

Bloom's Taxonomy, Leverrier's Algorithm, Pole Clustering, DC-DC Converter, Dynamic, Reduced-Order, Controller.

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Krishnaveni Rajamahendravarapu ¹, T. Vyshnavi ¹, A. Lavanya ¹, B. Sunitha Venkataseshamamba ¹, Gopinath Mummaleti ²

Affiliations
1 College of Food Science and Technology, Acharya N.G. Ranga Agricultural University, Bapatla - 522 101, Andhra Pradesh, IN
2 Department of Food Biotechnology, Indian Institute of Food Processing Technology, Thanjavur - 613 005, Tamil Nadu, IN

Abstract

The present study was carried out to evaluate the physical and nutritional properties of banana flour made using various drying techniques. The techniques such as sun, oven, fluidized bed and osmotic drying techniques were used in preparing banana flour. The study revealed that the bulk density of banana flour was 0.66 ± 0.01. The banana flour produced through solar drying was observed to have higher solubility of 9.3 % and the banana flour produced by osmotic drying exhibited lower solubility compared to other samples. The low moisture content of banana flour reveals that the product was shelf-stable and can be stored for longer time. The phenolic compounds were present in banana flour with good antioxidant capacity helps in protecting organs of the body. The banana flour can be a best alternative to wheat flour and gluten free products can be made and also a best natural functional ingredient that can be used in various food products as a thickener.

Keywords

Banana, Drying, Nutrition, Flour, Thickener, Antioxidant

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