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Item Reduction of neural network memories interconnections(UMT.Lahore, 2013) Warda HussainThis research work proposes a detailed methodology for the reductions of interconnections of neural associative memories using Very Large Scale Integration. For data storage, various techniques have been employed in the past few decades and several improvements have been made regarding size, speed and capacity of memory. Content Addressable Memory (CAM) is a special type of memory which is relatively faster as compared to other memory techniques because the data is retrieved on the basis of partial information instead of using separate address bits. Using Hopfield neurobiological model, a computationally fast and inexpensive associative memory model is proposed. The proposed model is implemented with the reduced input vector length in VLSI that results in the sufficient reduction of the number of neurons to be integrated on a chip. By reducing the input vector length, the number of interconnections is reduced in CAM, consequently the order of multiplications during the formation of trans-conductance matrix is decreased that eventually leads towards a functionally compact and cost efficient CAM design. The proposed methodology is implemented on MATLAB/Simulink. The simulation results verify that the CAM designed using reduced vector length based neural associative memory model is highly efficient with respect to time, space and cost. Although the formulation described here, is independent of hardware yet it provides a complete analytical base for compact, efficient and inexpensive CAM design using simulation tools.Item Transformer less design of polymer exchange membrane fuel cell based uninnteruptable power supply(UMT.Lahore, 2013) Syed Mohsin AliThis research work presents a transformer less model of fuel cell powered uninterruptable power supply (UPS). The design consideration of this research includes the utilization of Polymer Exchange Membrane Fuel Cell (PEMFC) market available stack model and designing of an efficient, low loss, cheap and high power design of a transformer less inverter model for 6kW UPS. This model is controlled with the help of embedded controller which ensures ripple and glitch free voltage regulated inverter providing pure sine wave as an output. This efficient inverter uses high frequency ferrite core transformer which would have a very small size and high efficiency. This model also ensures a very low total harmonic distortion. The proposed model utilizes a super capacitor module to overcome the electric transient conditions for the instantaneous power fluctuation, slow dynamics of the fuel cell and idealizing the overload response. Finally with synchronization techniques this UPS is connected to AC supply mains, also the calculations of fuel required for one hour continuous operation of 6kW UPS is formulated. The model proposed in this research work is implemented in MATLAB – SIMULINK environment.Item Equivalent model development and grid integration of a solid oxide fuel cell(UMT.Lahore, 2013) Muhammad SalikThe research work reported in this thesis is based on mathematical modeling of solid oxide fuel cell (SOFC) and its integration with grid. With the recent advancements in electrochemistry and the increasing demands for environment friendly energy resources, fuel cell technology has gained the major significance due to its compact size, low chemical emissions and low maintenance. Among different types of fuel cells, high temperature SOFC’s are capable for the stand alone high power production and grid-tied applications. Also the increase in demand for electric power, the distributed generation (DG) has attained much attention. DG utilizes alternate energy resources such as photovoltaic systems, wind energy systems and fuel cells. SOFC has proved to be a promising technology for distributed power generation with compact size, high power efficiency and absence of moving parts. SOFC is used as a reliable energy source in case of steady operations, but it shows slow response in case of transient conditions. Researchers have been working from past few years on modeling of SOFC to visualize its behavior under certain conditions. Most of the research articles do not include the detail of losses in SOFC which must be included in the equivalent model for analyzing the actual behavior of the SOFC over the time. In this research work, a mathematical model for a SOFC accounting for thermodynamic limits, effect of temperature and pressure variations is formulated to evaluate and visualize its actual characteristics. Activation, ohmic and mass transport over potentials are also included in the model. For connection of SOFC with grid, an intermediate module (Power Conditioning Unit) is proposed. Power Conditioning Unit (PCU) improves the slow response of SOFC and also steps up the DC voltages. It consists of a boost converter and a 3-phase inverter. PCU sets technical challenges in order to integrate SOFC with the utility grid. The overall modeling and integration of SOFC with the utility grid covers, the detailed representations of equivalent model of SOFC, power electronic modules, transformers and the grid integration technique. The proposed model is implemented in MATLAB-SIMULINK. It can be utilized for visualization of optimum characteristics and operation of grid integrated SOFC stack and its behavior under various operating conditions.