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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