Sri Ramakrishna Engineering College

About: Sri Ramakrishna Engineering College is a based out in . It is known for research contribution in the topics: Computer science & Control theory. The organization has 1030 authors who have published 843 publications receiving 3822 citations.

Design of digital pulse width modulator architecture with digital PID controller for DC-DC converter using FPGA

Abstract: A digital pulse width modulation architecture (DPWM) along with digital proportional integral derivative (PID) controller to control the DC-DC converter is presented in this paper. Difference between the actual output voltage and the reference voltage is calculated as error value. The look up table is created for PID controller to store the duty cycle ratio and the error value of power converters. Multipliers used in conventional algorithms are replaced by look up tables in the proposed work that enable the compact and low power implementation of digital controllers. DPWM architecture is developed with gray logic against the binary logic used in traditional DPWM architectures. Usage of gray counter also leads to low power consumption in the DPWM architecture. The proposed architecture is designed using Verilog hardware language and realized using field programmable gate array. PWM signals with varying duty cycle percentage can be derived from the proposed architecture. The generated PWM signal can control the switching condition of power converter to regulate the output voltage. Duty cycle percentage ranging from 16 to 96% can be developed with the proposed architecture. Simulation and experimental results of the architecture validate the proposed architecture. PWM signal with maximum operating frequency of 59.49 MHz and 60.22 MHz for SPARTAN 3A and SPARTAN 3E respectively can be generated with the proposed architecture.

A New Dual Tree Wavelet Based Image Denoising Using Fuzzy Shrink and Lifting Scheme

Abstract: Images are often corrupted by noise owing to channel communication errors, defective image acquisition plans or devices, engine sparks, power interference and atmospheric electrical emissions. In proposed method a new wavelet shrinkage algorithm based on fuzzy logic and the lifting scheme is used. In particular, intra-scale dependency within wavelet coefficients is modeled using a fuzzy feature. This fuzzy feature differentiates between important coefficients, namely, image discontinuity coefficients and noisy coefficients. The same is used for enhancing wavelet coefficients' information in the shrinkage step, which results in the fuzzy membership function shrinking the wavelet coefficients based on the fuzzy feature. Examine that the proposed image denoising algorithm in the new shiftable and modified version of discrete wavelet transform, is the dual-tree discrete wavelet transform. Also that the lifting scheme is there it allows a faster implementation of the WT and a fully in-place calculation of the WT. In addition, no extra memory is needed and the original signal can be replaced with its WT. The method transforms an image into the wavelet domain using lifting based wavelet filters in the wavelet domain and finally transforms the result into the spatial domain and the fuzzy threshold is used to extract out the Speckle in highest subbands. Experimental Result shows that the resultant enhanced image obtained has a better performance in noise suppression and edge preservation.

Studies on Ignition Delay and Flame Spread in High-Performance Solid Rocket Motors

Abstract: Accurate prediction of ignition delay and flame spread rate in solid propellant rocket motors is of great topical interest. In this paper using a standard k-ω turbulence model numerical studies have been carried out to examine the influence of solid rockets port geometry on ignition delay and the flame spread pattern. We observed that with the same inflow conditions and propellant properties heat flux histories and ignition time sequence are different for different port geometries. We conjectured from the numerical results that in solid rocket motors with highly loaded propellants, mass flux of the hot gases moving past the burning surface is large. Under these conditions, the convective flux to the surface of the propellant will be enhanced, which in turn enhance the local Reynolds number. This amounts a reduction in heat transfer film thickness and enhanced heat transfer to the propellant with consequent enhancement in the dynamic burn rate resulting the undesirable starting pressure transient. We concluded that, the more accurate description of gas phase to surface heat transfer process will give a better prediction and control of ignition delay and flame spread rate in solid propellant rockets.

Linux-Based Elevator Control System

Abstract: This proposed system is elaborated for designing an elevator of normal working and includes features that automatically work on some emergency situations like fire identification in the building (FID), earthquake (EQK), and also water flow detection in the building accurately with a platform-free development environment. On the basis of encoder pulse provided from the JGA25–370, a DC geared motor with quadrature encoder’s step signals provided in two different channels, the direction and the floor leveling can be identified. It includes STM8S103F3, an ARM minimum system development board, as the stand-alone microcontroller for this project as the direction of the elevator body (CAR) can be controlled by in-CAR operating panel (COP) which includes CAR call push buttons with the help of Small Device C Compiler in Ubuntu 16.04. This brings an IDE less and more reliable programming area that can be self-made according to product specification and also N-floored building using No Cabinet (NC) elevator that uses no landing calls.