Torque Control

This book is the result of inspirations and contributions from many researchers, a collection of 9 works, which are, in majority, focalised around the Direct Torque Control and may be comprised of three sections: different techniques for the control of asynchronous motors and double feed or double star induction machines, oriented approach of recent developments relating to the control of the Permanent Magnet Synchronous Motors, and special controller design and torque control of switched reluctance machine

Traction axial flux motor-generator for hybrid electric bus application

Tato dizertační práce se zabývá návrhem původního motor-generátoru s axiálním tokem a buzením permanetními magnety, zkonstruovaným specificky pro hybridní elektrický autobus. Návrhové zadání pro tento stroj přineslo požadavky, které vedly k této unikátní topologii tak, aby byl dosažen výkon, účinnost a rozměry stroje. Tato partikulární topologie motor-generátoru s axiálním tokem je výsledkem literární rešerše, kterou následoval výběr koncepce stroje s představeným návrhem jako výsledkem těchto procesů. Přístup k návrhu stroje s axiálním tokem sledoval „multi-fyzikální“ koncepci, která pracuje s návrhem elektromagnetickým, tepelným, mechanickým, včetně návrhu řízení, v jedné iteraci. Tím je v konečném návrhu zajištěna rovnováha mezi těmito inženýrskými disciplínami. Pro samotný návrh stroje byla vyvinuta sada výpočtových a analytických nástrojů, které byly podloženy metodou konečných prvků tak, aby samotný návrh stroje byl přesnější a spolehlivější. Modelování somtného elektrického stroje a celého pohonu poskytlo představu o výkonnosti a účinnosti celého subsytému v rozmanitých operačních podmínkách. Rovněž poukázal na optimizační potenciál pro návrh řízení subsystému ve smyslu maximalizace účinnosti celého pohonu. Bylo postaveno několik prototypů tohoto stroje, které prošly intensivním testováním jak na úrovni sybsytému, tak systému. Samotné výsledky testů jsou diskutovány a porovnány s analytickými výpočty parametrů stroje. Poznatky získané z prvního prototypu stroje pak sloužily k představení možností, jak zjednodušit výrobu a montáž stroje v příští generaci. Tato práce zaznamenává jednotlivé kroky během všech fází vývoje elektrického stroje s axiálním tokem, počínaje výběrem konceptu stroje, konče sumarizací zkušeností získaných z první generace prototypu tohoto stroje.This thesis deals with a design of a novel Axial-Flux Permanent Magnet Motor-Generator for a hybrid electric bus application. Thus, the design specification represents a set of requirements, which leads toward a concept of a unique topology meeting performance, efficiency and dimensional targets. The particular topology of the Axial-Flux Permanent Magnet Motor-Generator discussed in this work is an outcome of deep literature survey, followed by the concept selection stage with the layout of the machine as an outcome of this processes. The design approach behind this so-called Spoke Axial-Flux Machine follows an idea of multiphysics iterations, including electromagnetic, thermal, mechanical and controls design. Such a process behind the eventually proposed design ensured a right balance in between all of these engineering disciplines. A set of bespoke design and analysis tools was developed for that reason, and was backed up by extensive use of Finite-Element Analysis and Computational Fluid Dynamics. Therefore, the actual machine design gained higher level of confidence and fidelity. Modelling of the machine and its drive provided understanding of performance and efficiency of the whole subsystem at various operational conditions. Moreover, it has illustrated an optimization potential for the controls design, so that efficiency of the machine and power electronics might be maximized. Several prototypes of this machine have been built and passed through extensive testing both on the subsystem and system level. Actual test results are discussed, and compared to analytical predictions in terms of the machine's parameters. As a lesson learned from the first prototype of this machine, a set of redesign proposals aiming for simplification of manufacturing and assembly processes, are introduced. This work records steps behind all phases of development of the Axial Flux Machine from a basic idea as an outcome of concept selection stage, up to testing and wrap-up of experience gained from the first generation of the machine.

Modelling, simulation and real time implementation of a three phase AC to AC matrix converter

Matrix converters (MCs) are essentially forced commutated cycloconverters with inherent four quadrant operation consisting of a matrix of bidirectional switches such that there is a switch for each possible connection between the input and output lines. Matrix converter directly converts the AC input voltage at any given frequency to AC output voltage with arbitrary amplitude at any unrestricted frequency without the need for a dc link capacitor storage element at the input side.The introduction of bidirectional switches using power transistors and IGBTs made easy realization of the matrix converter. The real development of the matrix converter starts with the work of Venturini and Alesina who proposed a mathematical analysis and introduced the Low-Frequency Modulation Matrix concept to describe the low frequency behavior of the matrix converter [1-3]. In this, the output voltages are obtained by multiplication of the modulation matrix or transfer matrix with the input voltages. One of the essential requirements for switching three phase AC to three phase AC MC is that two or more bidirectional switches connected to any one output phase should NOT be closed simultaneously, as this will cause dangerously high short circuit current. Similarly any one bidirectional switch connected to each output phase should remain closed to provide a current path with inductive load.This thesis mainly provides an account of the three phase AC to three phase AC MC modelling concept with SIMULINK software using fundamental Venturini and Optimum Venturini modulation algorithm [1-8], advanced modulation algorithm such as that proposed by Sunter-Clare [11-12] and by Ned Mohan [13-14, 16-17], application of these algorithms for the Vector control of three phase Induction Motor (IM) drive [15], real time hardware in the loop simulation [51,54-55] for a three phase AC to single phase AC MC, three phase AC to three phase AC Multilevel MC (MMC) with three [18-19] and six flying capacitors per output phase using PSCAD software (as SIMULINK started shooting trouble), Indirect (ISVM) [25-30] and Direct (DASVM, DSSVM, CZASVM) [31-38] Space Vector Modulation, newly discovered dual programmable AC to DC rectifier concept using three phase AC to three phase AC MC [43-45], Delta-Sigma Modulated MC [46-49] and single phase AC to three phase AC MC [50].In addition a novel concept of a single phase / three phase AC to single phase / three phase AC converter using a DC link, complementary N and P MOSFETs and IGBTs is presented. A chapter on model verification is also presented where selected SIMULINK models from various chapters have been verified by using either PSCAD or PSIM software. An appendix on PIC microcontroller PIC16F84A application to saw-tooth carrier waveform generation and switching three phase AC to three phase AC converters using a DC link is added. Another appendix on speed control and brake by plugging of three phase induction motor fed by matrix converter is presented. List of publications from this thesis is presented on third appendix

Design definition of a mechanical capacitor

A design study and analyses of a 10 kW-hr, 15 kW mechanical capacitor system was studied. It was determined that magnetically supported wheels constructed of advanced composites have the potential for high energy density and high power density. Structural concepts are analyzed that yield the highest energy density of any structural design yet reported. Particular attention was paid to the problem of 'friction' caused by magnetic and I to the second power R losses in the suspension and motor-generator subsystems, and low design friction levels have been achieved. The potentially long shelf life of this system, and the absence of wearing parts, provide superior performance over conventional flywheels supported with mechanical bearings. Costs and economies of energy storage wheels were reviewed briefly

Solid state transformer technologies and applications: a bibliographical survey

This paper presents a bibliographical survey of the work carried out to date on the solid state transformer (SST). The paper provides a list of references that cover most work related to this device and a short discussion about several aspects. The sections of the paper are respectively dedicated to summarize configurations and control strategies for each SST stage, the work carried out for optimizing the design of high-frequency transformers that could adequately work in the isolation stage of a SST, the efficiency of this device, the various modelling approaches and simulation tools used to analyze the performance of a SST (working a component of a microgrid, a distribution system or just in a standalone scenario), and the potential applications that this device is offering as a component of a power grid, a smart house, or a traction system.Peer ReviewedPostprint (published version

Wind Power

This book is the result of inspirations and contributions from many researchers of different fields. A wide verity of research results are merged together to make this book useful for students and researchers who will take contribution for further development of the existing technology. I hope you will enjoy the book, so that my effort to bringing it together for you will be successful. In my capacity, as the Editor of this book, I would like to thanks and appreciate the chapter authors, who ensured the quality of the material as well as submitting their best works. Most of the results presented in to the book have already been published on international journals and appreciated in many international conferences

Renewable Energy

Renewable Energy is energy generated from natural resources - such as sunlight, wind, rain, tides and geothermal heat - which are naturally replenished. In 2008, about 18% of global final energy consumption came from renewables, with 13% coming from traditional biomass, such as wood burning. Hydroelectricity was the next largest renewable source, providing 3% (15% of global electricity generation), followed by solar hot water/heating, which contributed with 1.3%. Modern technologies, such as geothermal energy, wind power, solar power, and ocean energy together provided some 0.8% of final energy consumption. The book provides a forum for dissemination and exchange of up - to - date scientific information on theoretical, generic and applied areas of knowledge. The topics deal with new devices and circuits for energy systems, photovoltaic and solar thermal, wind energy systems, tidal and wave energy, fuel cell systems, bio energy and geo-energy, sustainable energy resources and systems, energy storage systems, energy market management and economics, off-grid isolated energy systems, energy in transportation systems, energy resources for portable electronics, intelligent energy power transmission, distribution and inter - connectors, energy efficient utilization, environmental issues, energy harvesting, nanotechnology in energy, policy issues on renewable energy, building design, power electronics in energy conversion, new materials for energy resources, and RF and magnetic field energy devices

Operational behavior of a double-fed permanent magnet generator for wind turbines

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (leaves 117-118).Greater efficiency in wind turbine systems is achieved by allowing the rotor to change its rate of rotation as the wind speed changes. The wind turbine system is decoupled from the utility grid and a variable speed operation is implemented. Since wind speed varies, the shaft speed should too. But electrical output frequency should be synchronous and Induction machines on their own do not allow for variable ratio of shaft speed to electrical frequency. Permanent Magnet (PM) machines have major advantages: Efficiency and power density are both high: they are also inherently synchronous. A prototype ([approx]20 kW) of a novel hybrid machine that encompasses the desired features of Permanent Magnet Generators and Doubly-Fed Induction Generators (DFIGs) is being built. This novel geometry machine has to be tested for stability on a test-bed and controlled using an appropriate power electronics and controller circuit. A MATLAB 5th order model of the machine is built, linearized. simulated and examined for stability. The dynamics of the PM rotor is studied. The electrical equivalent behavior of this component of the machine is vital because the frequency of the output power is a direct function of its mechanical speed. As a culmination of this research work, possible paths for the scope of future work on this technology is presented.(cont.) Keywords: wind turbines, modified torus geometry, permanent magnet, doubly-fed induction. dynamic state-space model, electromechanical stability analysis.by Sivananda Kumjula Reddy.S.M