92 research outputs found

    A NOVEL MULTIPHASE BIDIRECTIONAL FLY-BACK CONVERTER TOPOLOGY IS APPLIED TO INDUCTION MOTOR DRIVE

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    Hybrid Electric Vehicle (HEV) is an emerging technology in the modern world because of the fact that it mitigates environmental pollutions and at the same time increases fuel efficiency of the vehicles. Bi-directional Fly – back Converter controls electric drive of HEV of high power and enhances its performance which is the reflection of the fact that it can generate Constant voltages. For hybrid electric vehicles, the batteries and the drive dc link may be at different voltages. The batteries are at low voltage to obtain higher volumetric efficiencies, and the dc link is at higher voltage to have higher efficiency on the motor side. Therefore, a power interface between the batteries and the drive’s dc link is essential. This power interface should handle power flow from battery to motor, motor to battery, external gen-set to battery, and grid to battery. This paper proposes a multi-power-port topology which is capable of handling multiple power sources and still maintains simplicity and features like obtaining high gain, wide load variations, lower output-current ripple, and capability of parallel-battery energy due to the modular structure. The scheme incorporates a transformer winding technique which drastically reduces the leakage inductance of the coupled inductor. The development and testing of a bidirectional fly-back dc–dc converter for hybrid electric vehicle is described in this paper. Simple hysteresis voltage control is used for dc-link voltage regulation. The simulation results are presented, and modeling the circuit by using MATLAB/SIMULINK Platform

    Hydrothermal Synthesis, Microstructure and Photoluminescence of Eu3+-Doped Mixed Rare Earth Nano-Orthophosphates

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    Eu3+-doped mixed rare earth orthophosphates (rare earth = La, Y, Gd) have been prepared by hydrothermal technology, whose crystal phase and microstructure both vary with the molar ratio of the mixed rare earth ions. For LaxY1–xPO4: Eu3+, the ion radius distinction between the La3+ and Y3+ is so large that only La0.9Y0.1PO4: Eu3+ shows the pure monoclinic phase. For LaxGd1–xPO4: Eu3+ system, with the increase in the La content, the crystal phase structure of the product changes from the hexagonal phase to the monoclinic phase and the microstructure of them changes from the nanorods to nanowires. Similarly, YxGd1–xPO4: Eu3+, Y0.1Gd0.9PO4: Eu3+ and Y0.5Gd0.5PO4: Eu3+ samples present the pure hexagonal phase and nanorods microstructure, while Y0.9Gd0.1PO4: Eu3+ exhibits the tetragonal phase and nanocubic micromorphology. The photoluminescence behaviors of Eu3+ in these hosts are strongly related to the nature of the host (composition, crystal phase and microstructure)

    Design and Implementation of POSIT Based Adder and Multiplier in Verilog HDL

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    Due to recent developments, the POSIT number system, winch has been planned as a successor for numbers that are expressed in IEEE floating-point, which are in the focus of advances in arithmetic. Although this format claims to deliver more precise outcomes with the same bit width as ordinary floating point, the duration of the operation fluctuation during posit field identification poses a hardware design problem. The POSIT-based MAC Unit is created using Verilog HDL in this study, and the designed architecture is evaluated for good operation before being implemented on an FPGA using Xilinx Vivado

    Performance analysis of 4-bit ternary adder and multiplier using CNTFET for high speed arithmetic circuits

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    Multiple valued logic (MVL) can represent an exponentially higher number of data/information compared to the binary logic for the same number of logic bits. Compared to the conventional devices, the emerging device technologies such as Graphene Nano Ribbon Field Effect Transistor (GNRFET) and carbon nanotube field effect transistor (CNTFET) appears to be very promising for designing MVL logic gates and arithmetic circuits due to some exceptional electrical properties such as the ability to control the threshold voltage. This variation of the threshold voltage is one of the prescribed techniques to achieve multiple voltage levels to implement the MVL circuit.This work presents a 4-input ternary adder using carbon nanotube field effect transistor (CNTFET). Many researchers have been done work on implementation of ternary adders and multipliers. But no one has done the comparison of this proposed ternary adder with different types of nano transistors. Hence this work has been proposed a design of low power and high speed 4-input adder which will be useful for designing of fast ternary multipliers. All the proposed designs have been simulated using emerging device such as CNTFET at 32nm technology node. From the simulations, we have calculated the power consumptions of the proposed designs, carry propagation delay and power delay product for the CNTFET circuits. It has been observed that CNTFET based proposed logic circuits given a better performance than the conventional logical circuits

    High-Temperature Superconducting Dc Networks

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    Chitosan Coatings Modified with Nanostructured ZnO for the Preservation of Strawberries

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    Strawberries are highly consumed around the world; however, the post-harvest shelf life is a market challenge to mitigate. It is necessary to guarantee the taste, color, and nutritional value of the fruit for a prolonged period of time. In this work, a nanocoating based on chitosan and ZnO nanoparticles for the preservation of strawberries was developed and examined. The chitosan was obtained from residual shrimp skeletons using the chemical method, and the ZnO nanoparticles were synthesized by the close-spaced sublimation method. X-ray diffraction, scanning electron microscopy, electron dispersion analysis, transmission electron microscopy, and infrared spectroscopy were used to characterize the hybrid coating. The spaghetti-like ZnO nanoparticles presented the typical wurtzite structure, which was uniformly distributed into the chitosan matrix, as observed by the elemental mapping. Measurements of color, texture, pH, titratable acidity, humidity content, and microbiological tests were performed for the strawberries coated with the Chitosan/ZnO hybrid coating, which was uniformly impregnated on the strawberries’ surface. After eight days of storage, the fruit maintained a fresh appearance. The microbial load was reduced because of the synergistic effect between chitosan and ZnO nanoparticles. Global results confirm that coated strawberries are suitable for human consumption
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