255 research outputs found

    Design of High Efficiency Brushless Permanent Magnet Machines and Driver System

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    The dissertation is concerned with the design of high-efficiency permanent magnet synchronous machinery and the control system. The dissertation first talks about the basic concept of the permanent magnet synchronous motor (PMSM) design and the mathematics design model of the advanced design method. The advantage of the design method is that it can increase the high load capacity at no cost of increasing the total machine size. After that, the control method of the PMSM and Permanent magnet synchronous generator (PMSG) is introduced. The design, simulation, and test of a permanent magnet brushless DC (BLDC) motor for electric impact wrench and new mechanical structure are first presented based on the design method. Finite element analysis based on the Maxwell 2D is built to optimize the design and the control board is designed using Altium Designer. Both the motor and control board have been fabricated and tested to verify the design. The electrical and mechanical design are combined, and it provides an analytical IPMBLDC design method and an innovative and reasonable mechanical dynamical calculation method for the impact wrench system, which can be used in whole system design of other functional electric tools. A 2kw high-efficiency alternator system and its control board system are also designed, analyzed and fabricated applying to the truck auxiliary power unit (APU). The alternator system has two stages. The first stage is that the alternator three-phase outputs are connected to the three-phase active rectifier to get 48V DC. An advanced Sliding Mode Observer (SMO) is used to get an alternator position. The buck is used for the second stage to get 14V DC output. The whole system efficiency is much higher than the traditional system using induction motor

    Free piston expander with a variable built-in volume ratio and with an integrated linear alternator

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    Review on the conversion of thermoacoustic power into electricity

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    Thermoacoustic engines convert heat energy into high amplitude acoustic waves and subsequently into electric power. This article provides a review of the four main methods to convert the (thermo)acoustic power into electricity. First, loudspeakers and linear alternators are discussed in a section on electromagnetic devices. This is followed by sections on piezoelectric transducers, magnetohydrodynamic generators, and bidirectional turbines. Each segment provides a literature review of the given technology for the field of thermoacoustics, focusing on possible configurations, operating characteristics, output performance, and analytical and numerical methods to study the devices. This information is used as an input to discuss the performance and feasibility of each method, and to identify challenges that should be overcome for a more successful implementation in thermoacoustic engines. The work is concluded by a comparison of the four technologies, concentrating on the possible areas of application, the conversion efficiency, maximum electrical power output and more generally the suggested focus for future work in the field.Comment: The following article appeared in J. Acoust. Soc. Am 143(2) and the final version in a proper two-column format may be found at: http://scitation.aip.org/content/asa/journal/jasa/143/2/10.1121/1.502339

    Electrolysis of neodymium oxide. Final report for the period August 19, 1991 through February 28, 1997

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    INVESTIGATION OF STARTING BEHAVIOUR OF A FREE PISTON LINEAR GENERATOR ENGINE

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    The current global crisis is now wrapped around the transportation industry whereby emissions and fuel prices are increasing. It is clear that the transportation system have polluted globally with CO, NOx and soot. Due to the reasons mentioned, environmental policymakers have created laws that limit the emission level produced by the internal combustion engine. As a result, it pushes researchers to develop new methods and technologies to tackle this problem and to come up with a highly efficient internal combustion engine with lower emissions. A two-stroke free piston linear-generator engine (FPLG) as prime mover for electric power generation has been developed to address these issues. A linear engine coupled to a permanentmagnet assembly becomes a linear-generator (LG) which can produce electrical power. Its working principle is based on the free-piston two-stroke engine with direct injection

    Improving the torque quality of a modulated pole machine

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    PhD ThesisThe research work carried out in this thesis is collaboration between Newcastle University and Höganäs AB, Sweden. A topology, termed ‘Separate Phase MPM’ was initially developed by Newcastle University and Höganäs where the machine takes advantage of mutual flux paths in order to increase the torque density of the machine, however had high cogging torque and back EMF harmonic content. The work presented in this thesis was carried out with an overall aim to minimise the cogging torque and back EMF harmonics in the Modulated Pole Machine (MPM) topology aimed toward electric bicycles. Various techniques are proposed and verified in this thesis to reduce the magnitude of unwanted voltage and torque harmonics, providing a smoother riding experience. Finite Element Analysis was carried out using Infolytica MagNet® on various design techniques which ultimately stemmed in 24 motor prototypes being constructed and tested during this PhD. The measured results are compared with each other to approve the technique that provides the optimum motor performance. It is shown that the peak cogging torque is reduced by 90% while the back EMF harmonics are diminished too, with a minor 2% reduction in mean back EMF. The efficiency and peak torque of the optimum motor is 8% and 10% higher, respectively, when compared with the base motor used in this study

    FEASIBILITY STUDY OF NUCLEAR POWER FOR DISASTER CONTROL AND CONSTRUCTION BATTALION OPERATIONS. BEACHHEAD PLANT

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    Mathematical Approaches to Modeling, Optimally Designing, and Controlling Electric Machine

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    Optimal performance of the electric machine/drive system is mandatory to improve the energy consumption and reliability. To achieve this goal, mathematical models of the electric machine/drive system are necessary. Hence, this motivated the editors to instigate the Special Issue “Mathematical Approaches to Modeling, Optimally Designing, and Controlling Electric Machine”, aiming to collect novel publications that push the state-of-the art towards optimal performance for the electric machine/drive system. Seventeen papers have been published in this Special Issue. The published papers focus on several aspects of the electric machine/drive system with respect to the mathematical modelling. Novel optimization methods, control approaches, and comparative analysis for electric drive system based on various electric machines were discussed in the published papers
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