Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.

Este trabalho investiga o comportamento transitório da topologia de turbina eólica baseada em Doubly Fed Induction Generator (DFIG) ao simular faltas nos terminais do estator e rotor da máquina. Um modelo DFIG foi simulado no software Matlab/Simulink utilizando uma fonte de tensão com equivalente de Thévenin para simular a rede elétrica, um transformador de interface, uma máquina de indução de 2,0MVA e conversores fonte de tensão de dois níveis VSC conectados na topologia back-to-back. O controle dos conversores foi concebido a partir da estratégia de controle vetorial utilizando controladores PI projetados a partir do Método Ótimo Simétrico. A proteção crowbar e proteção de corrente dos conversores também foram implementados na simulação e depois validados para simular o comportamento aproximado do sistema DFIG real e, assim, verificar o comportamento transitório do DFIG no momento de faltas monofásicas, bifásicas e trifásicas nos terminais da máquina. Essa pesquisa possibilitou analisar o transitório eletromagnético a partir de gráficos de grandezas coletadas em vários pontos do sistema no momento dos disturbios, permitindo mostrar a influência do conversor back-to-back no comportamento do sistema, além de proporcionar uma base teórica do modelamento dinâmico, detalhar o projeto de controle do conversor back-to-back e projetar duas das principais proteções do sistema DFIG. Para isso, foi simulado seis casos de falta nos terminais da máquina, coletado gráficos e feito análises detalhadas do comportamento de nove grandezas distintas. Este trabalho proporciona uma base teórica do modelamento dinâmico, detalhamento do projeto de controle do conversor back-to-back, projeto de duas das principais proteções do sistema DFIG e análise do comportamento dinâmico do sistema máquina-conversores no momento de distúrbios. / This work investigates the behavior of the topology of the wind turbine based on Doubly Fed Induction Generator (DFIG) when simulating faults in the stator and rotor machine terminations. A DFIG model was simulated in the Matlab / Simulink software using a Thevenin voltage source equivalent to simulate an electrical network, an interface transformer, a 2,0MVA induction machine and two-level VSC voltage source converters connected in the back-to-back topology. The converter\'s control was conceived from the vector control strategy using PI controllers tuned with Symmetric Optimum Method. The crowbar protection and current protection of the inverters were also implemented in the simulation and then validated to simulate the approximate behavior of the real DFIG system and then to verify the transient behavior of the DFIG at the moment of singlephase, two-phase and three-phase faults at the machine terminals. This research makes it possible to analyze the electromagnetic transient from graphs of quantities collected at various points of the system at the time of the disturbances, allowing to show the influence of the back-to-back converter on the behavior of the system, in addition to a theoretical basis of dynamic modeling, detailing the control design of the back-to-back converter and designing two of the main DFIG system protections. For this, six fault cases were simulated at the machine terminals, collected graphs and performed detailed analyzes of the behavior of nine different quantities. This work provides a theoretical basis for dynamic modeling, detailing the control design of the back-to-back converter, designing two of the main protections of the DFIG system and analyzing the dynamic behavior of the machine-converter system at the time of disturbances. The objective of this investigation is to discover information still scarce in the literature about the transient behavior of the DFIG topology, including the generating unit, CC link and converters at the moment of internal faults to the system.

abstract: With the increasing penetration of converter interfaced renewable generation into power systems, the structure and behavior of the power system is changing, catalyzing alterations and enhancements in modeling and simulation methods. This work puts forth a Hybrid Electromagnetic Transient-Transient Stability simulation method implemented using MATLAB and Simulink, to study power electronic based power systems. Hybrid Simulation enables detailed, accurate modeling, along with fast, efficient simulation, on account of the Electromagnetic Transient (EMT) and Transient Stability (TS) simulations respectively. A critical component of hybrid simulation is the interaction between the EMT and TS simulators, established through a well-defined interface technique, which has been explored in detail. This research focuses on the boundary conditions and interaction between the two simulation models for optimum accuracy and computational efficiency. A case study has been carried out employing the proposed hybrid simulation method. The test case used is the IEEE 9-bus system, modified to integrate it with a solar PV plant. The validation of the hybrid model with the benchmark full EMT model, along with the analysis of the accuracy and efficiency, has been performed. The steady-state and transient analysis results demonstrate that the performance of the hybrid simulation method is competent. The hybrid simulation technique suitably captures accuracy of EMT simulation and efficiency of TS simulation, therefore adequately representing the behavior of power systems with high penetration of converter interfaced generation. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2018

Tese de mestrado integrado. Engenharia Mecânica (Opção de Automação). Faculdade de Engenharia. Universidade do Porto. 2010

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Automação). Faculdade de Engenharia. Universidade do Porto. 2010

Long haulage of heavy-duty trucks weighing over 15-ton stands for nearly 50% of the fuelconsumption among trucks, making them the most fuel consuming category. This indicatesthe potential benefits in improving the fuel efficiency for said category. Hybridization is onepossible solution.Hybrid vehicles are vehicles with two or more power sources in the powertrain. Differentpowertrain configurations, hybridization levels and hybrid concepts are best suitedfor different applications. With prices for fossil fuels constantly rising hybridization is animportant technology to improve fuel efficiency.Different variations of configurations and concepts enables many choices when decidingon a hybrid driveline. A simulation tool for efficiently comparing various hybrid drivelineswould be a great asset when deciding on a configuration for a certain vehicle application. Forthis thesis the application in focus is the previously mentioned category, a heavy duty longhauler weighing 36-ton.The modeling approach used for the simulation tool is called quasistatic modeling or"backward modeling". This name comes from, based on a chosen drive cycle, the resistingforces which act on the vehicle can statically be calculated at each step from the velocityprofile. The required power to drive along the drive cycle can then be calculated backwardswithin the powertrain resulting in a fuel consumption for the combustion engine. For thisthe free QSS-toolbox for Matlab Simulink has been used as a base and modified when needed.The configuration chosen to be implemented is a parallel electric hybrid and was chosenfor its good characteristics for the type of driving highways provide. For this configurationtwo types of controllers are used, one being an Equivalent Consumption Minimization Strategycontroller and the other a simple, rule based heuristic controller.The results for both controllers show small benefits with hybridization of the longhauler compared with the conventional which in the long run would make bigger differencebecause of the large consumption in whole. A sensitivity analysis was also done showingthat improving conventional vehicle parameters can be as beneficial as hybridization.

CPAP is the most common treatment for moderate to severe sleep apnea in adults. Despite its efficacy, patients’ safety, comfort and compliance are issues to be considered and improved in CPAP design. The issues include condensation, carbon dioxide in inhaled air, humidity and temperature of inhaled air. When a CPAP user breaths deeply, there will be some air not fully expelled and may be driven back into the heated air delivery tube (HADT). An interest has existed in what impacts this so called reverse flow may bring about to the CPAP use. The main objectives of this research are to quantify the reverse flow and its influence on carbon dioxide re-breathing, delivered humidity to the patient and condensation in the HADT. Within this thesis, two computer models of the CPAP system have been constructed on Simulink™ in the Matlab™ environment. One is about the CPAP fluid dynamic performance and carbon dioxide re-breathing and the other is on thermodynamic performance. The models can predict the dynamic behaviour of the CPAP machine. They are able to mimic the breath induced airflow fluctuation, and flow direction changes over wide real working ranges of ambient conditions, settings and coefficients. These models can be used for future analysis, development, improvement and design of the machine. The fluid dynamic and thermodynamic models were experimentally validated and they have proved to be valuable tool in the work. The main conclusions drawn from this study are: • Reverse flow increases when breaths load increases and pressure setting decreases. • Reverse flow does not definitely add exhaled air to the next inhalation unless the reverse flow is relatively too much. • Mask capacity does not influence the reverse flow. • The exhaled air re-breathed is mainly due to that stays in the mask, therefore larger mask capacity increases the exhaled air re-breath and the percentage of exhaled air in next inhalation drops when the breath load increases. • Deep breathing does not significantly change the total evaporation in chamber. • When deep breathing induced reverse flow occurs, condensation occurs or worsens in the HADT near the mask. This happens only when the humidity of the airflow from the CPAP is much lower than that of the exhaled air and the tube wall temperature is low enough for condensation to occur. • The deep breathing and reverse flow do not significantly influence the average inhaled air temperature. • The overall specific humidity in inhaled air is lower under deep breathing. • Mask capacity does not influence the thermal conditions in the HADT and the inhaled air specific humidity. Also the mask capacity does not significantly influences the inhaled air temperature.

<p>I JAS 39 Gripen finns funktioner, kallade uppdragsberäkningar, som informerarpiloten om hur mycket bränsle och tid som förväntas gå åt för att slutföra detaktuella flyguppdraget. Uppdragsberäkningsdelen är stor och komplex och genomatt göra en modell av uppdragsberäkningarna kan man enklare simulera och verifieradem innan införandet av en ändring. I detta examensarbete har en modellav koden implementerats i MATLAB/Simulink.</p><p>Under arbetet har en bränsleberäkningskärna och en accelerationsberäkningsfunktionmodellerats. I samband med modelleringen har modelleringsmetoder utvecklatsför vanligt förekommande dataobjekt och funktionaliteter i koden, såsom variabler,loopar och if-satser. En stor del av arbetet har handlat om validering av modellen mot originalkoden. Valideringen är något som skulle behövas automatiserasför att effektivisera modelleringsarbetet.</p><p>Förbättringar av de befintliga uppdragsberäkningarna har föreslagits och undersökts.Till exempel har statiska och dynamiska modeller av ett modellfel skapatsmed hjälp av multipel linjär regression och systemidentifieringsteori. Då dessa modelleranvändes minskade skillnaden mellan modellernas skattade bränsleflöde ochdet verkliga bränsleflödet. En del av förbättringarna som presenteras är enkla attimplementera i befintlig kod medan andra kräver betydligt mer anpassning. Dagensuppdragsberäkningar har visat sig komplicerade att modellera i Simulink. Islutet av rapporten presenteras ett konceptförslag, baserat på ett reglerteknisktangreppsätt, på hur uppdragsberäkningarna skulle kunna omarbetas för att passaSimulink bättre.</p>

<p>Matlab Simulink is a commonly used tool in the design process of control systems. To further take advantage of the Matlab Simulink models it is desirable to translate them for realtime use together with the possibility to read/write physical signals. </p><p>Real-Time Workshop is an extension to Simulink that automatically generates code from a model to a variety of target platforms. RTAI and RTLinux are hard realtime operating systems, making use of Linux. </p><p>To make automatically generated code run on RTAI and RTLinux an adaptation of the generation of code is necessary. </p><p>To control, for example, an automotive engine a data acquisition card with an appropriate device driver is required. Comedi, an open source project, provides a number of device drivers for data acquisition cards. </p><p>The developed system makes use of Simulink, Real-Time Workshop, RTAI or RTLinux, and the standard data acquisition card NI 6035E using a Comedi device driver. The Simulink models may be executed at frequencies up to 50 kHz on ordinary PC hardware. </p><p>The evaluation of the system consisted of measuring the interrupt latency of the used motherboard's bus, measuring computation times running Simulink models with known complexity, running models developed at Vehicular Systems and a comparison of interfacing Simulink/Real-Time Workshop between RTAI and RTLinux. </p><p>The recommended realtime operating system is RTAI due to the open source community support of it as a target platform for Real-Time Workshop.</p>

<p>The development in electronics increases the demand for good design methods and design tools in the field of electrical engeneering. To improve their design methods Ericsson Microwave Systems AB is interested in using computer tools to create a link between the specification and the implementation of a digital system in a FPGA. </p><p>Xilinx System Generator for DSP is a tool for implementing a model of a digital signalprocessing algorithm in a Xilinx FPGA. To evaluate Xilinx System Generator two testcases has been designed. </p><p>The testcases are selected to represent the FPGA designs made at Ericsson Microwave Systems. The testcases show that Xilinx System Generator can be used to effectivly implement a model made in Simulink in a FPGA from Xilinx. The result of the implementation is comparable to the implementation of VHDL code written by hand. </p><p>The use of tools for implementation of a model in hardware cause change in the design methods used at Ericsson Microwave Systems. The higher level of abstraction introduced by System Generator results in the design decisions made at system level having a higher impact on the final realization.</p>