Mohamed A. Shrud

A study of modeling and simulation for interleaved buck converter

This paper focuses on modeling, analysis and simulation of a 42V/14V dc/dc converter based architecture. This architecture is considered to be a technically viable solution for automotive dual-voltage power system in passenger cars of the near future. An interleaved dc/dc converter system is chosen for the automotive converter topology due to its advantages regarding filter reduction, dynamic response, and power management. Presented herein, is a model based on one kilowatt interleaved six-phase buck converter designed to operate in a Discontinuous Conduction Mode (DCM). The control strategy of the converter is based on a voltage-mode-controlled Pulse Width Modulation (PWM) with a Proportional-Integral-Derivative (PID). The effectiveness of the interleaved step-down converter is verified through simulation using control-oriented simulator, MatLab/Simulink.

Interleaved Boost DC-DC Converter Using Delta-Sigma Modulation Suitable for Renewable Energy Applications

 Abstract—It is generally accepted that interleaving techniques are efficient at reducing the input/output ripples and increasing the power output of boost converters operating in critical conduction mode.Pulse width modulation (PWM) is used to produce the switching pattern. But this technique causes large switching noise peaks at a multiple number of the carrierfrequency. This paper proposes Interleaved Boost DC- DC suitablefor renewable energy applications. The proposed converterutilizes delta-sigma modulation to control pulse generator. A thorough and effective analysis of the converter is carried out in order to achieve the system stability and to improve the dynamic performance. The output response obtained by this method is very much improved compared to the conventional PWM method of control. Simulation results are provided to illustrate the advantages of the proposed converter and controller scheme. All the advantages of interleaving, such as higher efficiency and reduced ripple for voltage/current, are also achieved in the proposed converter.

Towards an Efficacious Storage Performance in Virtualised Environment

Server virtualisation has dramatically reshaped the information technology industry in recent years. There are too many variants to consider. This paper proposes a practical method of achieving efficacious disk performance in a virtualized environment. Remote disk access in a virtualized environment is emerging as one of the mainstream network intensive applications, with large demands for disk and network bandwidth. As a performance metric we investigate the efficiency and effectiveness of using multi controllers combined with disk alignments. We investigate on how to deliver optimized storage input/output performance and availability at the lowest possible cost and present best practices that we demonstrated on our implementation of VSphere based Oracle installations. We also propose mechanisms to prevent common performance issues like interface queue saturation. Our findings suggest that an underutilized storage system can mask environment misconfigurations. Once the storage system becomes busier, these misconfigurations can cause performance issues. Similarly, storage performance issues are rarely due to a single cause, for example, we had virtual machine misalignment and background process contention. We also concluded that when we use mixed disk technologies in the same storage area network and stress one type with writes, this can also have a negative impact on the others due to the load on the storage controller. In addition to this, we also found that misalignment affects write latency more than the read operations.

Distributed EO-STBC with one-bit feedback scheme for bi-directional cooperative wireless dual-antenna relay networks

This paper presents a half-duplex amplify-and-forward (AF) two-way wireless relay networks (TWRNs) with two terminal nodes and two relay nodes each having two antennas. A distributed extended orthogonal space time block coding (D-EOSTBC) with one-bit feedback scheme based on the selection of phase rotation has been implemented. In this feedback scheme, only one-bit feedback is applied at the relay nodes to extract full cooperative diversity gain and array gain at each terminal node. The transmission symbols from the antennas of each relay node are rotated according to the feedback from the terminal nodes which is equivalent to rotating the phases of the corresponding channel coefficients. The simulation results show that the one-bit feedback scheme achieves an improved system performance with lower feedback overhead compared to previously reported feedback schemes.

Development of Automotive DC/DC Converter based Centralised Architecture

This paper presents the technical development, modeling, analysis and simulation of a 42V/14V dc/dc converter based architecture for dual/high voltage automotive electrical power system. It overcomes some of the limitations of traditional automotive electrical power system topology that use 14V power net. The proposed system simulation model composed of a 4kW/42V power generation system buffered by a 36V energy storage battery and a 1kW/14V interleaved six-phase buck converter. The effectiveness of the developed model of the complete dc/dc converter-based centralised system architecture is verified through simulation results using control-oriented simulator, MatLab/Simulink.