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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Simulation numérique CEM du test BCI (Bulk Current Injection) de la norme aéronautique DO 160 / EMC numerical simulation of BCI test based on aeronautic standard DO 160 (FUI17)

Diop, Mor Sokhna 28 September 2017 (has links)
Ces travaux de recherche présentent une modélisation/Simulation du Test BCI (Bulk Current Injection) sous contrainte RTCA – DO 160, test de qualification des équipements très contraignant en termes de coûts et délais. Lors de sa réalisation, il présente aussi beaucoup de disparités dont il est parfois difficile d’identifier les sources et de les maîtriser lors du test avec une maquette physique. La simulation présente tout son intérêt dans l’étude de ces phénomènes (qui peuvent avoir un impact non moins significatif sur les résultats de test) mais aussi la répétabilité des essais.Dans un premier temps, une méthode de modélisation du couplage pince d’injection de courant et câbles est établie qui tient compte de l’évolution en fonction de la fréquence du noyau de ferrite du transformateur RF (Pince de courant) et des paramètres linéiques des câbles. Deux modèles sont principalement proposés dans ces travaux :- Un modèle générique, modèle circuit constitué uniquement d’éléments passifs RLC et élaboré (sous SPICE) à partir de la mesure des paramètres S. Ce modèle fait apparaitre la zone de couplage entre pince et câbles au secondaire.- Un modèle magnétique, macro-modèle développé sous le logiciel Flux2D. Les paramètres géométriques du modèle sont renseignés à partir de la connaissance des dimensions de la pince (diamètres intérieur /extérieur, longueur) et des câbles (diamètres/longueurs). Les paramètres physiques de la pince de courant particulièrement la perméabilité magnétique complexe du noyau de ferrite est obtenue à partir de la mesure du coefficient de réflexion au port d’entrée de la pince et extraction en post-traitement.Les validations dans le domaine fréquentiel ont été effectuées avec une bonne corrélation entre simulations et mesures dans la bande BCI [10 kHz – 400 MHz]. Ces résultats obtenus ont permis l'élaboration d'un modèle complet du test BCI (sous l’outil logiciel PAM-CEM/CRIPTE) qui tient compte d’un toron aéronautique complexe et de l’EST (Équipement Sous Test modélisé au laboratoire Ampère de Lyon). Il est constitué du générateur de perturbation (qui fait office de pince d’injection de courant), du modèle du toron de câbles (constitué de paires torsadées blindées, de paires non-blindées, …) et de l’EST (Équipement Sous Test) dans la bande [10 kHz – 400 MHz]. La bonne concordance entre simulations et mesures laisse présager une utilisation par les avionneurs ou équipementiers pour des études paramétriques concernant le test BCI (influence de la disposition des câbles, queue de cochon, longueur toron, disposition de l’EST par rapport au plan de masse, …) et/ou pour une virtualisation dans une phase de pré-qualification des équipements.Mots clés : CEM (Compatibilité ElectroMagnétique), Test BCI (Bulk Current Injection), Modélisation/Simulation, Norme aéronautique DO 160. / This work presents a modeling/simulation approach of BCI (Bulk Current Injection) test under constraint RTCA - DO 160. This qualification test of equipment is very constraining in terms of cost and deadline. During the test, there are also many disparities for which it is difficult to identify sources (and control them) with a physical test setup. The simulation is of interest in the study of phenomena (which can have negative impacts on test results) but also the repeatability of tests.First, a method of modeling for the probe/cables coupling is established which takes into account the variation with frequency of the RF transformer (current probe) of the magnetic ferrite core and the linear parameters of cables (skin/ proximity effects). Two models are proposed in this work:- A generic model which is made up solely of passive elements RLC and elaborated (with SPICE software) from the measurement of S-parameters. It shows the coupling zone between probe and cables (secondary winding).- A magnetic macro-model developed with the Flux2D software. Its geometrical parameters are defined from dimensions of the probe (inner/outer diameter, length) and cables (diameters / length). Physical parameters of the current probe, particularly the complex magnetic permeability of the ferrite core, are obtained from measurement of the S-parameter at the input port of the probe and post-treatment extraction.Frequency domain validations were performed with a good correlation between simulations and measurements in the BCI band ([10 kHz - 400 MHz]).These results led to the development of a complete virtual BCI test (with PAM-CEM / CRIPTE software), which take into account an aeronautic complex harness and a DUT (Device Under Test which is modeled at Ampère laboratory). It consists of disturbance generator, harness model (consisting of shielding twisted cables, no shielding cables, etc.) and DUT (Device Under Test) in the band [10 kHz - 400 MHz].The good correlation between simulations and measurements suggests a use by the aircraft manufacturers or equipment manufacturers for parametric studies about BCI test (uncertainties related to cable positions, pigtail, cable length, DUT position with respect to the ground plane, ...) and /or for virtualization in a pre-qualification phase of the equipment.Keywords: EMC (ElectroMagnetic Compatibility), BCI (Bulk Current Injection) test, Modeling/Simulation, DO 160 aeronautic standard.
2

Unbalanced Distributed Distribution Network Fault Analysis and Smart Grid Application

Ou, Ting-Chia 24 November 2010 (has links)
A direct and rigid algorithm approach based on Equivalent Current Injection (ECI) for large-scale distribution power flow analysis is proposed in this dissertation. This algorithm used two primary matrices: BI and ZV-BC. Two matrices, which are built from the topological characteristics of distribution networks, are used to achieve the power flow solutions. BI matrix is the bus injection to branch current matrix and the ZV-BC matrix describes the relationship between the bus voltage mismatches and the branch current. The building algorithm is easily programmable and can be accomplished by a simple search technique with the two proposed matrices. Four connected cases are considered in this dissertation. The proposed algorithm is robust and accurate. Test results demonstrate the potential and validity of the proposed algorithm in distribution applications. Secondly, this thesis also presents a fault analysis with hybrid compensation for unbalanced distribution systems is proposed. The method employs the unbalanced three-phase model to analyze faults. BI and ZV-BC matrices containing information of the topological characteristics of distribution networks were built along with the proposed hybrid compensation method for analysis. Appropriate boundary conditions can be obtained for a fault to solve various types of single or simultaneous faults. The time-consuming LU decompositions, the Jacobian matrix, or the Y admittance matrix, required in the traditional algorithms, are not needed in the new development. Test results show that the proposed method is efficient, easy to program, also with advantages of high speed, robustness, improved accuracy, and lower memory requirements. This thesis also presents a hybrid programming (HP) technique to solve the reconfiguration problem for loss reduction and service restoration in Smart Grid application.
3

Voltage Stability Study for Dynamic Load with Modified Orthogonal Particle Swarm Optimization

Lin, Wu-Cheng 24 June 2011 (has links)
The thesis use capacitors, Static Synchronous Compensator (STATCOM) and wind generator to get optimal voltage stability for twenty-four-hour dynamic load by compensating real/reactive power. In the thesis, Modified Orthogonal Particle Swarm Optimizer (MOPSO) is proposed to find the sitting and sizing of capacitors, STATCOM and wind generator, and integrate Equivalent Current Injection (ECI) algorithm to solve Optimal Power Flow (OPF) to achieve optimal voltage stability. The algorithm uses MOPSO to renew STATCOM and wind turbine sizing Gbest with multiple choices and Taguchi orthogonal array, which improves Particle Swarm Optimizer (PSO) without falling into the local optimal solution and searches optimal voltage stability of power system by load balancing equation and inequality constraints. Average Voltage Variation (AVV) and Average Voltage Drop Variation (AVDV) are proposed as objective function to calculate whole system voltage variations, and convergence test of MOPSO. The IEEE 33 Bus distribution system and Miaoli-Houlong distribution system were used for simulation to test the voltage control during peak and off-peak periods of Taipower. Compensation of real/reactive power was used to get optimal system voltage stability for each simulated case.
4

Distribution Network Modeling and Capacitor Placement Application

Su, Yuh-Sheng 14 August 2002 (has links)
Enhancing the quality of services in the distribution system is an important topic for power system research. It is imperative to employ precise network modeling and effective simulation tools, and a good system model is the key. This dissertation starts with modifying the building algorithms of Y-admittance and Z-impedance matrices. The Y-matrix will be built according to phase sequences. With the facts that the line self-impedance is significantly greater than the mutual-coupling terms and the existence of a high r/x ratio in distribution, two decoupled load flow methods (Phase-Decoupled¡BPD and Sub-Phase-Decoupled¡BSPD) with Current Injection Model(CIM) were developed. A new Z-matrix building algorithm was also developed in this dissertation. It decomposed the traditional Z into two sub-matrices, the upper and lower triangular matrices respectively. The matrices represent the relationships between the branch current and the bus injection current, and between the bus voltage and the branch current. Enhancing the quality of services will be effectively achieved by a proper capacitor placement technique. This dissertation develops a linear relationships of voltage changes versus the capacitor compensation, the branch current changes versus the capacitor compensation, and loss reductions versus the capacitor compensation. For loss reduction, a linear optimization function was defined to solve the capacitor placement problem. Tests have shown that the proposed methods were suitable for applications to an unbalance distribution system.
5

Controls for High Performance Three-Phase Switched Reluctance Motors

Pasquesoone, Gregory 17 August 2011 (has links)
No description available.
6

Voltage Unbalance Mitigation in Low Voltage Distribution Networks using Time Series Three-Phase Optimal Power Flow

Al-Ja'afreh, M.A.A., Mokryani, Geev 12 October 2021 (has links)
No / Due to high penetration of single-phase Photovoltaic (PV) cells into low voltage (LV) distribution networks, several impacts such as voltage unbalance, voltage rise, power losses, reverse power flow arise which leads to operational constraints violation in the network. In this paper, a time series Three Phase Optimal Power Flow (TPOPF) method is proposed to minimize the voltage unbalance in LV distribution networks with high penetration of residential PVs. TPOPF problem is formulated using the current injection method in which the PVs are modelled via a time-varying PV power profile with active and reactive power control. The proposed method is validated on a real LV distribution feeder. The results show that the reactive power management of the PVs helps mitigate the voltage unbalance significantly. Moreover, the voltage unbalance index reduced significantly compared to the case without voltage unbalance minimisation. / Innovate UK GCRF Energy Catalyst Pi-CREST project under Grant number 41358; British Academy GCRF COMPENSE project under Grant GCRFNGR3\1541; Mut’ah University, Jordan
7

Full-band Structure Calculations of Optical Injection in Semiconductors: Investigations of One-color, Two-color, and Pump-probe Scenarios

Rioux, Julien 11 January 2012 (has links)
Carrier, spin, charge current, and spin current injection by one- and two-color optical schemes are investigated within 30-band k·p theory. Parameters of the band model are optimized to give full-Brillouin zone band structures for GaAs and Ge that give accurate Γ-point effective masses and gyromagnetic factors and give access to the L valley, and to the E₁ and E₁+Δ₁ critical points in the linear optical absorption. Calculations of one- and two-photon carrier and spin injection and two-color current injection are performed for excitation energies in the range of 0—4 eV in GaAs and 0—3.5 eV in Ge. Significant spin and spin current injection occurs with 30% spin polarization in GaAs and Ge at photon energy matching the E₁ critical point. Further, the anisotropy and disparity of the current injection between parallel and perpendicular linearly-polarized beam configurations are calculated. For light propagating along a <111> crystal axis, anisotropic contributions in coherent current control and two-photon spin injection give rise to normal current components and in-plane spin components. In Ge, contributions from the holes to spin, electrical current, and spin current injection are investigated. Optical orientation results in 83% spin-polarized holes at the band edge. The effects of carrier dynamics in Ge are treated within a rate-equation model. The detection of spin dynamics in a pump-probe setup is considered, and the Fermi-factor approach is justified for electrons but not for holes. Carrier and current injection are further investigated in single-layer and bilayer graphene within the tight-binding model. In single-layer graphene, the linear-circular dichroism in two-photon absorption yields an absorption coefficient that is twice as large for circularly polarized light compared to linearly polarized light. Coherent current injection is largest for co-circularly polarized beams and zero for cross-circularly polarized beams. For linearly polarized beams, the magnitude of the injected current is independent of beam polarizations. In contrast, the injected current in bilayer graphene shows disparity between parallel and perpendicular configurations of the beams. The resulting angular dependence of the current is a macroscopic, measurable consequence of interlayer coupling in the bilayer.
8

Full-band Structure Calculations of Optical Injection in Semiconductors: Investigations of One-color, Two-color, and Pump-probe Scenarios

Rioux, Julien 11 January 2012 (has links)
Carrier, spin, charge current, and spin current injection by one- and two-color optical schemes are investigated within 30-band k·p theory. Parameters of the band model are optimized to give full-Brillouin zone band structures for GaAs and Ge that give accurate Γ-point effective masses and gyromagnetic factors and give access to the L valley, and to the E₁ and E₁+Δ₁ critical points in the linear optical absorption. Calculations of one- and two-photon carrier and spin injection and two-color current injection are performed for excitation energies in the range of 0—4 eV in GaAs and 0—3.5 eV in Ge. Significant spin and spin current injection occurs with 30% spin polarization in GaAs and Ge at photon energy matching the E₁ critical point. Further, the anisotropy and disparity of the current injection between parallel and perpendicular linearly-polarized beam configurations are calculated. For light propagating along a <111> crystal axis, anisotropic contributions in coherent current control and two-photon spin injection give rise to normal current components and in-plane spin components. In Ge, contributions from the holes to spin, electrical current, and spin current injection are investigated. Optical orientation results in 83% spin-polarized holes at the band edge. The effects of carrier dynamics in Ge are treated within a rate-equation model. The detection of spin dynamics in a pump-probe setup is considered, and the Fermi-factor approach is justified for electrons but not for holes. Carrier and current injection are further investigated in single-layer and bilayer graphene within the tight-binding model. In single-layer graphene, the linear-circular dichroism in two-photon absorption yields an absorption coefficient that is twice as large for circularly polarized light compared to linearly polarized light. Coherent current injection is largest for co-circularly polarized beams and zero for cross-circularly polarized beams. For linearly polarized beams, the magnitude of the injected current is independent of beam polarizations. In contrast, the injected current in bilayer graphene shows disparity between parallel and perpendicular configurations of the beams. The resulting angular dependence of the current is a macroscopic, measurable consequence of interlayer coupling in the bilayer.
9

Att skydda BLDC motorer mot oaktsam användning : Övervakning av temperatur i statorlindningar för handhållna produkter / To protect BLDC motors from inadvertent use : Temperature monitoring in stator windings for handheld products

Anders, Angrén, Jonathan, Pettersson January 2020 (has links)
Syfte – Syftet för denna studie var att utveckla en sensorlös modell som beräknar en estimeradtemperatur i en BLDC-motors statorlindningar, detta för att undersöka hur väl det går attskydda handhållna produkter mot oaktsam användning och för att kunna motverka körningunder höga temperaturer, vilket skulle kunna förlänga livslängden för handhållna produkter. Metod – Denna studie har använt forskningsmetoden Design Science Research för att utvecklaen artefakt som sensorlöst estimerar temperatur i en BLDC-motors statorlindningar.Artefaktens prestanda för den estimerade temperaturen var noggrannhet, precision ochkonvergeringstid, vilket utvärderats genom analys av kvantitativa data som samlats in underolika experiment. Resultat – Den utvecklade artefakten i studien baserades på en kombination av CurrentInjection och Lumped Parameter Thermal Network samt ett Kalman Filter, artefaktensprestanda uppfyllde inte Husqvarna AB:s krav. Artefaktens precision och noggrannhet för att estimera temperatur i en BLDCmotorsstatorlindningar blev 7,2 °C ± 23,8 °C och dess konvergeringstid blev 7,3 sför dess medelvärde och 18,4 s för dess precision. Implikationer – Denna studie och dess resultat kan användas som en hänvisning på hur välen kombination av Current Injection, Lumped Parameter Thermal Network och Kalman Filterkan estimera temperaturen i statorlindningar för BLDC-motorer med en resistans på 20 mΩ,induktans på 10 uH, nominell hastighet på ~20 000 RPM med terminering av typen Delta ochsom är icke salient. Begränsningar – Studiens begränsningar listas nedan. Utvecklingstiden för artefakten utfördes under begränsad tid. Vilket bidragit till mindre optimering av artefakterna. Vilket bidragit till färre iterationer av artefakter. Artefakten utvärderas endast på VESC hårdvara och dess mjukvara som grund.Artefaktens prestanda påverkas av noggrannheten samt precisionen vidmätning av ström och spänning. Experimenten som utfördes var begränsade. Hade intervallen som experimenten utfördes gällande temperatur, hastighetoch dynamisk last varit större skulle artefaktens prestanda kunna bli undersökti mer verkliga förhållanden. En bättre bromsbänk och en klimatkammareskulle använts. Endast en BLDC motor utvärderades. Utvärdering av fler motorer skulle kunna visa på skillnader i prestanda förartefakten mellan olika mindre motorer, det vill säga visa på dess generellatillämpbarhet. Analys av artefaktens prestanda vid enbart konvergerande tillstånd utfördes inte. Vilket skulle kunna visa på om artefaktens prestanda vid enbart konvergeradetillstånd hade uppfyllt Husqvarna AB:s krav. Nyckelord – Estimera Temperatur, BLDC-motor, Statorlindningar, Current Injection,Lumped Parameter Thermal Network, Kalman Filter, VESC / Purpose – The purpose of this study was to develop a sensorless model that calculates anestimated temperature in a stator winding of a BLDC motor, to investigate how well it is possibleto protect handheld products from inadvertent use and to be able to counteract operation underhigh temperatures, which could prolong service life of the handheld products. Method – This study has used the research method Design Science Research to develop anartifact that sensorlessly estimates temperature in a BLDC motor's stator windings. Theperformance of the artifact for the estimated temperature is accuracy, precision, andconvergence time, which was evaluated by analysing quantitative data collected during differentexperiments. Findings – The artifact developed in the study is based on a combination of Current Injectionand Lumped Parameter Thermal Network and a Kalman Filter, the performance of the artifactdid not meet Husqvarna AB's requirements. The precision and accuracy of the artifact for estimating temperature in a statorwinding of a BLDC motor was 7,2 °C ± 23,8 °C and its convergence time was 7,3 sfor its mean and 18,4 s for its precision. Implications – This study and its results can be used as a reference regarding how well acombination of Current Injection, Lumped Parameter Thermal Network and Kalman Filter canestimate the temperature in stator windings for non-salient BLDC motors with a resistance of20 mΩ, inductance of 10 uH, nominal speed of ~20 000 RPM with termination of the Deltatype. Limitations – The limitations of the study are listed below. The development time for the artifact was performed for a limited time. Which has contributed to less optimization of the artifacts. Which has contributed to fewer iterations of artifacts. The artifact is evaluated only on VESC hardware and its software as a basis.The performance of the artifact is affected by the accuracy and precision inmeasuring current and voltage. The experiments performed were limited. Had the intervals at which the experiments were performed regardingtemperature, speed and dynamic load been greater, the performance of theartifact could have been examined in more real conditions. A better brakebench and a climate chamber would be used. Only one BLDC motor was evaluated. Evaluation of more motors could show differences in the performance of theartifact between different smaller motors, that is, show its general applicability. Analysis of the performance of the artifact in convergent states alone was notperformed. Which could show if the performance of the artifact could fulfill HusqvarnaAB's requirements if the analysis were only performed in convergingconditions. Keywords – Estimate Temperature, BLDC Motor, Stator Windings, Current Injection,Lumped Parameter Thermal Network, Kalman Filter, VESC
10

Design methodologies for built-in testing of integrated RF transceivers with the on-chip loopback technique

Onabajo, Marvin Olufemi 15 May 2009 (has links)
Advances toward increased integration and complexity of radio frequency (RF) andmixed-signal integrated circuits reduce the effectiveness of contemporary testmethodologies and result in a rising cost of testing. The focus in this research is on thecircuit-level implementation of alternative test strategies for integrated wirelesstransceivers with the aim to lower test cost by eliminating the need for expensive RFequipment during production testing.The first circuit proposed in this thesis closes the signal path between the transmitterand receiver sections of integrated transceivers in test mode for bit error rate analysis atlow frequencies. Furthermore, the output power of this on-chip loopback block wasmade variable with the goal to allow gain and 1-dB compression point determination forthe RF front-end circuits with on-chip power detectors. The loopback block is intendedfor transceivers operating in the 1.9-2.4GHz range and it can compensate for transmitterreceiveroffset frequency differences from 40MHz to 200MHz. The measuredattenuation range of the 0.052mm2 loopback circuit in 0.13µm CMOS technology was 26-41dB with continuous control, but post-layout simulation results indicate that theattenuation range can be reduced to 11-27dB via optimizations.Another circuit presented in this thesis is a current generator for built-in testing ofimpedance-matched RF front-end circuits with current injection. Since this circuit hashigh output impedance (>1k up to 2.4GHz), it does not influence the input matchingnetwork of the low-noise amplifier (LNA) under test. A major advantage of the currentinjection method over the typical voltage-mode approach is that the built-in test canexpose fabrication defects in components of the matching network in addition to on-chipdevices. The current generator was employed together with two power detectors in arealization of a built-in test for a LNA with 14% layout area overhead in 0.13µm CMOStechnology (<1.5% for the 0.002mm2 current generator). The post-layout simulationresults showed that the LNA gain (S21) estimation with the external matching networkwas within 3.5% of the actual gain in the presence of process-voltage-temperaturevariations and power detector imprecision.

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