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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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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