Reluctance Accelerator Efficiency Optimization via Pulse Shaping

Reluctance accelerators are used to apply linear forces to ferromagnetic projectiles via solenoids. Ef ciency increases for a single-stage reluctance accelerator were produced by manipulating the input current pulse supplied by a discharging capacitor. The development of a theoretical model allowed for the calculation of optimized pulse shapes. A digital pulsewidth modulated switching method was used to control the current pulse shape using an Arduino Uno microcontroller, which supplied signals to the gate of a MOSFET transistor that controlled the current to the system solenoid. An ef ciency increase of 5.7% was obtained for a reluctance accelerator with an optimized current pulse shape in comparison to a capacitor discharge with no pulse shapin

The Efficiency of a Two-Stage Reluctance Accelerator through Pulse Shaping

An investigation considering the efficiency gains of electrical pulse-shaping for a two-stage reluctance accelerator system has been undertaken. An optimum gross efficiency of (1.36 ± 0.02)% was achieved, amounting to an increase of (290 ± 20)% relative to the performance of an equivalent single-stage accelerator. The performance increase due to pulse-shaping for a two-stage setup was found to surpass that achieved for this single-stage setup in terms of both efficiency and velocity. This investigation highlights the potential of pulse-shaping methods to increase the feasibility and flexibility of electrical acceleration for a variety of practical applications. The intention of this paper was to exhibit the potential of reluctance acceleration technology in multi-stage, initially by using a two-stage system. Possible avenues for further investigation are proposed, to build upon the results of this study

New trends in electrical vehicle powertrains

The electric vehicle and plug-in hybrid electric vehicle play a fundamental role in the forthcoming new paradigms of mobility and energy models. The electrification of the transport sector would lead to advantages in terms of energy efficiency and reduction of greenhouse gas emissions, but would also be a great opportunity for the introduction of renewable sources in the electricity sector. The chapters in this book show a diversity of current and new developments in the electrification of the transport sector seen from the electric vehicle point of view: first, the related technologies with design, control and supervision, second, the powertrain electric motor efficiency and reliability and, third, the deployment issues regarding renewable sources integration and charging facilities. This is precisely the purpose of this book, that is, to contribute to the literature about current research and development activities related to new trends in electric vehicle power trains.Peer ReviewedPostprint (author's final draft

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 07)

This bibliography is issued in two sections: Section 1 - Abstracts, and Section 2 - Indexes. This issue of the Abstract Section cites 158 patents and applications for patent introduced into the NASA scientific and technical information system during the period of January 1975 through June 1975. Each entry in the Abstract Section consists of a citation, an abstract, and, in most cases, a key illustration selected from the patent or application for patent. This issue of the Index Section contains entries for 2830 patent and application for patent citations covering the period May 1969 through June 1975. The index section contains five indexes -- subject, inventor, source, number and accession number

Comet composition and density analyzer

Distinctions between cometary material and other extraterrestrial materials (meteorite suites and stratospherically-captured cosmic dust) are addressed. The technique of X-ray fluorescence (XRF) for analysis of elemental composition is involved. Concomitant with these investigations, the problem of collecting representative samples of comet dust (for rendezvous missions) was solved, and several related techniques such as mineralogic analysis (X-ray diffraction), direct analysis of the nucleus without docking (electron macroprobe), dust flux rate measurement, and test sample preparation were evaluated. An explicit experiment concept based upon X-ray fluorescence analysis of biased and unbiased sample collections was scoped and proposed for a future rendezvous mission with a short-period comet

Particle Physics Reference Library

This third open access volume of the handbook series deals with accelerator physics, design, technology and operations, as well as with beam optics, dynamics and diagnostics. A joint CERN-Springer initiative, the “Particle Physics Reference Library” provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A,B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open acces

Multi-level-objective design optimization of permanent magnet synchronous wind generator and solar photovoltaic system for an urban environment application

This Ph.D. thesis illustrates a novel study on the analytical and numerical design optimization of radial-flux permanent magnet synchronous wind generators (PMSGs) for small power generation in an urban area, in which an outer rotor topology with a closed-slot stator is employed. The electromagnetic advantages of a double-layer fractional concentration non-overlapping winding configuration are discussed. The analytical behavior of a PMSG is studied in detail; especially for magnetic flux density distribution, time and space harmonics, flux linkages, back-EMF, cogging torque, torque, output power, efficiency, and iron losses computation. The electromagnetic behavior of PMSGs are evaluated when a number of various Halbach array magnetization topologies are presented to maximize the generator’s performance. In addition, the thermal behavior of the PMSG is improved using an innovative natural air-cooling system for rated speed and higher to decrease the machine’s heat mainly at the stator teeth. The analytical investigation is verified via 2-D and 3-D finite element analysis along with a good experimental agreement. Design optimization of electrical machines plays the deterministic role in performance improvements such as the magnetization pattern, output power, and efficiency maximization, as well as losses and material cost minimization. This dissertation proposes a novel multi-objective design optimization technique using a dual-level response surface methodology (D-RSM) and Booth’s algorithm (coupled to a memetic algorithm known as simulated annealing) to maximize the output power and minimize material cost through sizing optimization. Additionally, the efficiency maximization by D-RSM is investigated while the PMSG and drive system are on duty as the whole. It is shown that a better fit is available when utilizing modern design functions such as mixed-resolution central composite (MR-CCD) and mixed-resolution robust (MR-RD), due to controllable and uncontrollable design treatments, and also a Window-Zoom-in approach. The proposed design optimization was verified by an experimental investigation. Additionally, there are several novel studies on vibro-acoustic design optimization of the PMSGs with considering variable speed analysis and natural frequencies using two techniques to minimize the magnetic noise and vibrations. Photovoltaic system design optimization considered of 3-D modeling of an innovative application-oriented urban environment structure, a smart tree for small power generation. The horizon shading is modeled as a broken line superimposed onto the sun path diagram, which can hold any number of height/azimuth points in this original study. The horizon profile is designed for a specific location on the Barcelona coast in Spain and the meteorological data regarding the location of the project was also considered. Furthermore, the input weather data is observed and stored for the whole year (in 2016). These data include, ambient temperature, module’s temperature (open and closed circuits tests), and shading average rate. A novel Pareto-based 3-D analysis was used to identify complete and partial shading of the photovoltaic system. A significant parameter for a photovoltaic (PV) module operation is the nominal operating cell temperature (NOCT). In this research, a glass/glass module has been referenced to the environment based on IEC61215 via a closed-circuit and a resistive load to ensure the module operates at the maximum power point. The proposed technique in this comparative study attempts to minimize the losses in a certain area with improved output energy without compromising the overall efficiency of the system. A Maximum Power Point Track (MPPT) controller is enhanced by utilizing an advanced perturb & observe (P&O) algorithm to maintain the PV operating point at its maximum output under different temperatures and insolation. The most cost-effective design of the PV module is achieved via optimizing installation parameters such as tilt angle, pitch, and shading to improve the energy yield. The variation of un-replicated factorials using a Window-Zoom-in approach is examined to determine the parameter settings and to check the suitability of the design. An experimental investigation was carried out to verify the 3-D shading analysis and NOCT technique for an open-circuit and grid-connected PV module.Esta tesis muestra un novedoso estudio referente al diseño optimizado de forma analítica y numérica de un generador síncrono de imanes permanentes (PMSGs) para una aplicación de microgeneración eólica en un entorno urbano, donde se ha escogido una topología de rotor exterior con un estator de ranuras cerradas. Las ventajas electromagnéticas de los arrollamientos fraccionarios de doble capa, con bobinas concentradas se discuten ampliamente en la parte inicial del diseño del mismo, así como las características de distribución de la inducción, los armónicos espaciales y temporales, la fem generada, el par de cogging así como las características de salida (par, potencia generada, la eficiencia y la distribución y cálculo de las pérdidas en el hierro que son analizadas detalladamente) Posteriormente se evalúan diferentes configuraciones de estructuras de imanes con magnetización Halbach con el fin de maximizar las prestaciones del generador. Adicionalmente se analiza la distribución de temperaturas y su mejora mediante el uso de un novedoso diseño mediante el uso de ventilación natural para velocidades próximas a la nominal y superiores con el fin de disminuir la temperatura de la máquina, principalmente en el diente estatórico. El cálculo analítico se completa mediante simulaciones 2D y 3D utilizando el método de los elementos finitos así como mediante diversas experiencias que validan los modelos y aproximaciones realizadas. Posteriormente se desarrollan algoritmos de optimización aplicados a variables tales como el tipo de magnetización, la potencia de salida, la eficiencia así como la minimización de las pérdidas y el coste de los materiales empleados. En la tesis se proponen un nuevo diseño optimizado basado en una metodología multinivel usando la metodología de superficie de respuesta (D-RSM) y un algoritmo de Booth (maximizando la potencia de salida y minimizando el coste de material empleado) Adicionalmente se investiga la maximización de la eficiencia del generador trabajando conjuntamente con el circuito de salida acoplado. El algoritmo utilizado queda validado mediante la experimentación desarrollada conjuntamente con el mismo. Adicionalmente, se han realizado diversos estudios vibroacústicos trabajando a velocidad variable usando dos técnicas diferentes para reducir el ruido generado y las vibraciones producidas. Posteriormente se considera un sistema fotovoltaico orientado a aplicaciones urbanas que hemos llamado “Smart tree for small power generation” y que consiste en un poste con un generador eólico en la parte superior juntamente con uno o más paneles fotovoltaicos. Este sistema se ha modelado usando metodologías en 3D. Se ha considerado el efecto de las sombras proyectadas por los diversos elementos usando datos meteorológicos y de irradiación solar de la propia ciudad de Barcelona. Usando una metodología basada en un análisis 3D y Pareto se consigue identificar completamente el sistema fotovoltaico; para este sistema se considera la temperatura de la célula fotovoltaica y la carga conectada con el fin de generar un algoritmo de control que permita obtener el punto de trabajo de máxima potencia (MPPT) comprobándose posteriormente el funcionamiento del algoritmo para diversas situaciones de funcionamiento del sistemaLa tesis desenvolupa un nou estudi per al disseny optimitzat, analític i numèric, d’un generador síncron d’imants permanents (PMSGs) per a una aplicació de microgeneració eòlica en aplicacions urbanes, on s’ha escollit una configuració amb rotor exterior i estator amb ranures tancades. Es discuteixen de forma extensa els avantatges electromagnètics dels bobinats fraccionaris de doble capa així com les característiques resultats vers la distribució de les induccions, els harmònics espacials i temporals, la fem generada, el parell de cogging i les característiques de sortida (parell, potencia, eficiència i pèrdues) Tanmateix s’afegeix l’estudi de diferents estructures Halbach per als imants permanents a fi i efecte de maximitzar les característiques del generador. Tot seguit s’analitza la distribució de temperatures i la seva reducció mitjançant la utilització d’una nova metodologia basada en la ventilació natural. Els càlculs analítics es complementen mitjançant anàlisi en 2 i 3 dimensions utilitzant elements finits i diverses experiències que validen els models i aproximacions emprades. Una vegada fixada la geometria inicial es desenvolupen algoritmes d’optimització per a diverses variables (tipus de magnetització dels imants, potencia de sortida, eficiència, minimització de pèrdues i cost dels materials) La tesi planteja una optimització multinivell emprant la metodologia de superfície de resposta i un algoritme de Booth; a més, es realitza la optimització considerant el circuit de sortida. L’algoritme resta validat per la experimentació realitzada. Finalment, s’han considerat diversos estudis vibroacústic treballant a velocitat variable, emprant dues tècniques diferents per a reduir el soroll i les vibracions desenvolupades. Per a finalitzar l’estudi es considera un sistema format per una turbina eòlica instal·lada sobre un pal de llum autònom, els panells fotovoltaics corresponents i el sistema de càrrega. Per a modelitzar l’efecte de l’ombrejat s’ha emprat un model en 3D i les dades del temps i d’irradiació solar de la ciutat de Barcelona. El model s’ha identificat completament i s’ha generat un algoritme de control que considera, a més, l’efecte de la temperatura de la cèl·lula fotovoltaica y la càrrega connectada al sistema per tal d’aconseguir el seguiment del punt de màxima potenciaPostprint (published version

Theoretical and Experimental Investigations of a Permanent Magnet Excited Transverse Flux Machine with a Segmented Stator for In-Wheel Motor Applications

A three-phase transverse flux permanent magnet (PM) motor with flux concentrating (FC-) topology that has a segmented stator is studied in this dissertation. The phases of the stator have been placed around the rotational axis of the machine instead of placing them in a classical way over each other along the axial direction. Through this phase arrangement, the electrical and mechanical shifts between the phases are considered to ensure proper operation of the transverse flux machine (TFM) without the need of extra components such as a start-up capacitor or a special designed power supply. The segmented stator construction has required that the conventional ring coils to be replaced by a type of concentric winding that take a saddle shape enabling parallel magnetic circuits to take place. This has initiated studying the effect of the distances located between the phases on all over the performances of the machine. In order to select an initial construction for the stator, a preliminary assessment study of some conventional PM-TFMs having ring coils are carried out, through which they are re-designed as outer rotor motors and compared based on the level of electromagnetic torque and the inductance profile. As the main application of the design is to achieve a compact construction for an outer rotor, low noise and speed too for possible future in-wheel applications, the most interesting issue in this study is how to bring all the phases of the machine around the shaft in one layer without losing the torque productivity as when the phases are placed under each other in the conventional way. Therefore, the designed machine is set in further theoretical evaluation studies via finite element method (FEM) with the conventional layered TFM, and it shows that the TFM with segmented windings has a better torque density as its correspondence in the conventional layered structure. This result is in favor to the segmented structure, in particular, about 31% of the PMs number in the segmented structure (i.e., total number of PMs located between the phases) will not have an active role in the torque production. A detailed mathematical theory has been analytically developed and investigated to show the validity and limitation of the design. The study has incorporated how the segmentation of each phase and placement of the two parts opposite to each other can improve the mechanical balance of the TFM and hence quite rotation. The approach has been shown for two- and three-phase PM-TFMs. Moreover, illustration for applying the same principle of segmented stator to surface PM topology of TFMs is analytical verified and shown via FEM. Possible constructions with segmented stators are developed in a periodical table format to give the machine designer a shortcut for a possible construction with the selected number of magnets, number of segments per phase and the desired space between the phases. Since the noise is a well-known problem of TFMs, due to the ripple in the electromagnetic torque waveform and the natural magnetic normal forces, the normal and axial forces in PM-TFM with segmented stator have been investigated too, where introducing more segments per phase will reduce their effects. In order to validate the theoretical investigation, a low-scaled test machine is designed, constructed and a complete test bench has been built to experimentally test the machine. The experimental investigations have included generator and motor operation modes as well as measuring the ratings, performances of the machine and the starting methods. The test machine has reached via the conducted tests an average torque of about 2.1 Nm with an efficiency of 53% and it has a great development potential to be improved via shaping of stator poles, the room available for the windings, fill factor and more optimization possibilities. Based on the theoretical and experimental investigations, the operation of the segmented winding design of PM-TFM proves itself to work and to have a future for compact motors in industrial operation, or as in-wheel outer rotor motor for mobile platforms. For higher power applications, a machine with such type of stator should be designed with big diameters that will allow the utility of more PMs as well as more segments per phase, where both are involved in the torque production, i.e., more torque density for the segmented TFM

Multi-objective torque control of switched reluctance machine

PhD ThesisThe recent growing interest in Switched Reluctance Drives (SRD) is due to the electrification of many products in industries including electric/hybrid electric vehicles, more-electric aircrafts, white-goods, and healthcare, in which the Switched Reluctance Machine (SRM) has potential prospects in satisfying the respective requirements of these applications. Its main merits are robust structure, suitability for harsh environments, fault-tolerance, low cost, and ability to operate over a wide speed range. Nevertheless, the SRM has limitations such as large torque ripple, high acoustic noise, and low torque density. This research focuses on the torque control of the SRD with the objectives of achieving zero torque error, minimal torque ripple, high reliability and robustness, and lower size, weight, and cost of implementation. Direct Torque Control and Direct Instantaneous Torque Control are the most common methods used to obtain desired torque characteristics including optimal torque density and minimized torque ripple in SRD. However, these torque control methods, compared to conventional hysteresis current control, require the use of power devices with a higher rating of about 150% to achieve the desired superior performance. These requirements add extra cost, conduction loss, and stress on the drive’s semiconductors and machine winding. To overcome these drawbacks, a simple and intuitive torque control method based on a novel adaptive quasi sliding mode control is developed in this study. The proposed torque control approach is designed considering the findings of an investigation performed in this thesis of the existing widely used control techniques for SRD based on information flow complexity. A test rig comprising a magnet assisted SRM driven by an asymmetric converter is constructed to validate the proposed torque control method and to compare its performance with that of direct instantaneous torque control, and current hysteresis control methods. The simulation and experimental results show that the proposed torque control reduces the torque ripple over a wide speed range without demanding a high current and/or a high switching frequency. In addition, It has been shown that the proposed method is superior to current hysteresis control method in the sensorless operation of the machine. Furthermore, the sensorless performance of the proposed method is investigated with the lower component count R-Dump converter. The simulation results have also demonstrated the excellent controller response using the standard R-Dump converter and also with its novel version developed in this thesis that needs only one current sensor

Developments toward a Silicon Strip Tracker for the PANDA Experiment

The PANDA detector at the future FAIR facility in Darmstadt will be a key experiment in the understanding of the strong interaction at medium energies where perturbative models fail to describe the quark-quark interaction. An important feature of the detector system is the ability to reconstruct secondary decay vertices of short-lived intermediate states by means of a powerful particle tracking system with the the Micro-Vertex Detector (MVD) as central element to perform high-resolution charmonium and open-charm spectroscopy. The MVD is conceived with pixel detectors in the inner parts and double-sided silicon strip detectors at the outer half in a very lightweight design. The PANDA detector system shall be operated in a self-triggering broadband acquisition mode. Implications on the read-out electronics and the construction of the front-end assemblies are analyzed and evaluation of prototype DSSD-detectors wrt. signal-to-noise ratio, noise figures, charge sharing behavior, spacial resolution and radiation degradation discussed. Methods of electrical sensor characterization with different measurement setups are investigated which may be useful for future large-scale QA procedures. A novel algorithm for recovering multiple degenerate cluster hit patterns of double-sided strip sensors is introduced and a possible architecture of a Module Data Concentrator ASIC (MDC) aggregating multiple front-end data streams conceived. A first integrative concept for the construction and assembly of DSSD modules for the barrel part of the MVD is introduced as a conclusion of the thesis. Furthermore, a detailed description of a simplified procedure for the calculation of displacement damage in compound materials is given as reference which was found useful for the retrieval of non-ionizing energy loss for materials other than silicon.Der PANDA Detektor im zukünftigen FAIR-Beschleunigerkomplex in Darmstadt wird ein Schlüsselexperiment im Verständnis der starken Wechselwirkung bei mittleren Energien, bei denen kein Zugang über perturbative Methoden zur Quark-Quark Interaktion existiert, sein. Eine wichtige Eigenschaft des Detektorsystems, die Ortsrekonstruktion sekundärer Zerfallsvertizes kurzlebiger Zwischenzustände, wird dabei durch ein Spurverfolgungssystem mit dem Mikro-Vertex Detektor (MVD) als wichtigstem Element zur hochauflösenden Charmoniumund Open-Charm Spektroskopie garantiert. Der MVD ist konzipiert als leichtgewichtiges, geteiltes Silizium-Detektorsystem mit Pixeldetektoren im inneren Bereich und doppelseitigen Streifendetektoren (DSSD) in den äußeren Regionen. Das PANDA Detektorsystem soll in einem selbstgetriggertem Regime Daten breitbandig und ohne Totzeitverluste verarbeiten können. Die sich daraus ergebenden Implikationen auf den Aufbau der Ausleseelektronik und der Front-end-Baugruppen werden analysiert und es werden Ergebnisse von Messungen an DSSD-Prototypen im Hinblick auf Signal-zu-Rausch-Verhältnis, Rauscheigenschaften, Ladungsteilungsverhalten, Ortsauflösung und Bestrahlungstoleranz diskutiert. Methoden zur elektrischen Charakterisierung von Sensoren werden untersucht, die bei zukünftigen großangelegten QA-Untersuchungen nützlich eingesetzt werden können. Ein neuartiger Cluster- Korrelationsalgorithmus, welcher mehrfach entartete Clusterhit-Muster zu erkennen vermag wird ebenso vorgestellt wie eine mögliche Architektur des noch zu entwickelnden Module-Data- Concentrator ASIC (MDC), welcher die Datenströme der Front-end Chips auf Modulebene zusammenfassen soll. Ein erstes integratives Konzept für Konstruktion und Zusammenbau von DSSD-Modulen des Barrel-Bereichs des MVD wird im Abschluss der Dissertation vorgestellt. Darüber hinaus wird eine detaillierte Beschreibung einer vereinfachten Vorschrift zur Berechnung des Versetzungsschadens durch Neutronen in zusammengesetzten Stoffen angegeben, welche sich als nützlich für die Ableitung des nicht-ionisierenden Energieverlustes in Materialien neben Silizium erwiesen hat