This diploma thesis deals with the design of a partially integrated charge pump in 0.25 micron technology ACMOS. The work is divided into two main parts, theoretical and practical. The theoretical section describes in detail various topologies of higher voltage generation of a charge pump and selected methods of regulating the output voltage of charge pumps. The practical part deals with the the actual design of a charge pump together with the arguments for the choice of the TPVD topology and the type of the regulation. Three regulation methods of a charge pump were implemented, tested and are dealt with: Pulse Skip, Constant frequency and PWM. There are 3 sub chapters, each describing a different regulation method, defining all the key elements of the design of such a charge pump and the results of the simulations are discussed. Conclusion of the thesis summarizes the results of the design of charge pumps, comparing them on the basis of the chosen type of output voltage regulation.

The thesis describes theoretical and experimental studies on the chaotic behaviour of a peak current-mode controlled boost converter, a parallel two-module peak current-mode controlled DC-DC boost converter, and a peak current-mode controlled power factor correction (PFC) boost converter. The research concentrates on converters which do not have voltage control loops, since the main interest is in the intrinsic mechanism of chaotic behaviour. These converters produce sub-harmonics of the clock frequency at certain values of the reference current I[ref] and input voltage V[in], and may behave in a chaotic manner, whereby the frequency spectrum of the inductor becomes continuous. Non-linear maps for each of the converters are derived using discrete time modelling and numerical iteration of the maps produce bifurcation diagrams which indicate the presence of subharmonics and chaotic operation. In order to check the validity of the analysis, MATLAB/SIMULINK models for the converters are developed. A comparison is made between waveforms obtained from experimental converters, with those produced by the MATLAB/SIMULINK models of the converters. The experimental and theoretical results are also compared with the bifurcation points predicted by the bifurcation diagrams. The simulated waveforms show excellent agreement, with both the experimental waveforms and the transitions predicted by the bifurcation diagrams. The thesis presents the first application of a delayed feedback control scheme for eliminating chaotic behaviour in both the DC-DC boost converter and the PFC boost converter. Experimental results and FORTRAN simulations show the effectiveness and robustness of the scheme. FORTRAN simulations are found to be in close agreement with experimental results and the bifurcation diagrams. A theoretical comparison is made between the above converters controlled using delayed feedback control and the popular slope compensation method. It is shown that delayed feedback control is a simpler scheme and has a better performance than that for slope compensation.

Orientador: Falcondes Jose Mendes de Seixas / Banca: Carlos Alberto Canesin / Banca: Luiz Carlos Gomes de Freitas / Resumo: Este trabalho propõe um novo conversor CA-CC trifásico de múltiplos pulsos com estágios CC-CC elevadores de tensão controlados pela técnica de histerese constante. Nesta proposta não são empregados indutores de interfase. A finalidade deste conversor é a de possibilitar um barramento CC regulado para aplicações embarcadas, acionamentos elétricos e afins, sempre com preocupações relacionadas aos aspectos de Qualidade de Energia Elétrica. Assim, a proposta deve apresentar elevado fator de potência, baixa distorção harmônica total de corrente drenada da rede elétrica. Ampla revisão bibliográfica, reunindo as propostas mais recentes da literatura para conversores com mesma finalidade, é feita para que sejam estudadas as estruturas de potência, técnicas de controle, versatilidade, possibilidade de isolamento galvânico e robustez. Em seguida, é detalhada a proposta principal deste trabalho por meio da apresentação do equacionamento do autotransformador, dos estágios elevadores de tensão e da técnica de controle. Esta análise permite que sejam feitas simulações com todos os elementos do conversor CA-CC e então, se desenvolva o projeto físico dos elementos magnéticos e se escolham os componentes eletrônicos do protótipo. O número reduzido de componentes de controle e a simplicidade dos circuitos de potência são grandes atrativos da proposta discutida. Todas as informações relevantes são descritas detalhadamente e, sempre que possível, meios alternativos de solucionar problemas são também apresentados, de forma que fiquem claras as possibilidades de melhoria da técnica empregada. A operação conjunta de todos os elementos mais a técnica de controle foi validada, de maneira que se comprovou, por meio de ensaios, todos os princípios de funcionamento da proposta de conversor CA-CC. Pelos resultados experimentais, obteve-se corrente drenada... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work proposes a new AC-DC three-phase multipulse converter with DC-DC boost stages and constant hysteresis control. The objective of this converter is to provide a reliable DC bus for on-board applications, electric motor drives and similars, always considering power quality issues. Thus, the proposal presents high power factor and low harmonic distortions in the currents from the mains. A wide revision is made on other recent proposals found in the scientific literature. Different topologies are compared considering power circuits, control techniques, isolation possibility and robustness. The second chapter presents the details on the main proposal of this work and also the mathematical equations that describe the autotransformer, boost converters and control strategy. Later, simulation results are commented and discussed and the physical design is detailed. The output filter elements, power components and control elements are specified. Experimental results including main waveforms, efficiency, voltage regulation and temperature rise are presented for the autotransformer. The boost stages are also tested and its results are discussed. Finally, the proposed AC-DC converter is tested and the control technique applied to the power stage is validated / Mestre

In this work are described detail manuals of creating animations in two ways. 1. By means of presentation of breaking up the constraints. 2. By means of application Inventor Studio. Furthermore, there is described the principle functions of the DC motor. There is the procedure which can simulate the transient with Matlab Simulink. There is also explained how to measure engine parameters needed to calculate the transient.

The purpose of this study was to evaluate whether consumer orientation (active/passive) and psychological involvement (attitude, opinion, belief, and behavioral intention) affect satisfaction when dining in an ethnic restaurant. The sample represented 232 consumers who dined in participating Washington D.C. metropolitan area ethnic restaurants. Information was obtained by asking consumers to answer a four part, 86 item questionnaire. Correlation analysis revealed that opinion (r = 0.17, P < 0.04), belief (r = 0.28, P < 0.01), and behavioral intentions (r = 0.19, P < 0.02) of the active consumer significantly affect satisfaction. Whereas, for the passive consumer no significant effect was found. Results of the stepwise regression analysis revealed that consumer psychological involvement and restaurant attributes affect satisfaction with service (R² = 0.57, p<0.05), satisfaction with lunch (R² = 0.8, p<0.05), satisfaction with dinner (R² = 0.33, p<0.05), and satisfaction with the overall dining experience (R² = 0.39, p<0.0l). Further, it was found that consumers' future visitations, within the next few weeks, were affected by consumer's psychological involvement (R² = 0.53, p<0.0l). Restaurant attributes (speed of service; employee courtesy; and food quality and prices) affected overall satisfaction in dining (R² = 0.4, p<0.0l), but it weakly affected future visitations (R² = 0.04, p<0.04, negative Mallows' Coefficient). The findings of this study contribute not only to consumer self-concept theory and satisfaction theory but also have practical implications to the ethnic restaurant industry. / Ph. D.

This dissertation presents various systematic design techniques for photovoltaic (PV) source simulators to serve as a convenient tool for the dynamic performance evaluation of solar power conditioning systems and their maximum power point tracking algorithms. A well-designed PV source simulator should accurately emulate the static and the dynamic characteristic of actual PV generator. Four major design features should be adopted in any PV source simulator: (i) high power-stage efficiency, (ii) fast transient response-time, (iii) output impedance matching with actual PV generator, and (iv) precise reference generation technique. Throughout this research, two different PV source simulator systems are designed, modeled, and experimentally verified. The design of the first system focuses mainly on creating new reference generation techniques where the PV equivalent circuit is used to precisely generate the current-voltage reference curves. A novel technique is proposed and implemented with analog components to simplify the reference signal generator and to avoid computation time delays in digital controllers. A two-stage LC output filter is implemented with the switching power-stage to push the resonant frequency higher and thus allowing a higher control-loop bandwidth design while keeping the same switching ripple attenuation as in the conventional one-stage LC output filter. With typical control techniques, the output impedance of the proposed simulator did not  match the closed-loop output impedance of actual PV generator due to the double resonant peaks of the two-stage LC output filter. Design procedures for both control and power-stage circuits are explained. Experimental results verify the steady-state and transient performance of the proposed PV source simulator at around 2.7 kW output. The design concept of the first simulator system is enhanced with a new type of PV source simulator that incorporates the advantages of both analog and digital based simulators. This simulator is characterized with high power-stage efficiency and fast transient response-time. The proposed system includes a novel three-phase ac-dc dual boost rectifier cascaded with a three-phase dc-dc interleaved buck converter. The selected power-stage topology is highly reliable and efficient. Moreover, the multi-phase dc-dc converter helps improve system transient response-time though producing low output ripple, which makes it adequate for PV source simulators. The simulator circuitry emulates precisely the static and the dynamic characteristic of actual PV generator under different environmental conditions including different irradiance and temperature levels. Additionally, the system allows for the creation of the partial shading effect on PV characteristic. This dissertation investigates the dynamic performance of commercial and non-commercial solar power conditioning systems using the proposed simulator in steady-state and transient conditions. Closed-loop output impedance of the proposed simulator is verified at different operating conditions. The impedance profile --magnitude and phase- matches the output impedance of actual PV generator closely. Mathematical modeling and experimental validation of the proposed system is thoroughly presented based on a 2.0 kW hardware prototype. The proposed simulator efficiency including the active-front-end rectifier and the converter stages at the maximum power point is 96.4%. / Ph. D.

Arbetet med att konstruera en spänningsomvandlare med multipla utgångar med fokus på minimering av EMI har gjorts på TEMPEST Center Combitech i Växjö. Detta för att känslig mätutrustning behöver strömförsörjas utan att samtidigt påverka mätobjekten. För att konstruera en lösning bättre än de nätaggregat som används idag, med avseende på störningar, har beräkningar, simuleringar och mätningar gjorts. Kretsarna har konstruerats på kopplingsdäck och mätningar har gjorts med oscilloskop och i mätkammare. Omvandlarna består av en AC/DC-del med 230VAC till 24VDC och 4 olika utgångar med spänningsnivåer på 5VDC, 12VDC, 24VDC och 36VDC.

The interest of using direct current in networks for both transmission and distribution of power is increasing due to the higher efficiency compared to the alternating current used today. As no natural zero crossings exist in direct current, the interruption of fault currents becomes a challenge. Several circuit breaker topologies have been proposed to fulfill the requirements for DC grids. One such topology is the hybrid DC-breaker consisting of three parallel branches: a mechanical switch, a semiconductor branch, and a metal oxide varistor. The current interruption in the hybrid DC-breaker is made in three steps. A mechanical switch carries the nominal current with low losses during normal operation. When the breaker is tripped to interrupt the current, the mechanical switch is opened and commutates the current into the semiconductor branch. This branch will then conduct the current as the mechanical switch regains its voltage withstand. The semiconductors turn off and force the current into the varistor branch where the magnetic energy is absorbed and the current is forced to zero. This thesis is based on simulations and experiments to obtain design rules for such a DC-breaker. It has been shown that several aspects needs to be considered. Simulations are performed with several different models to obtain the requirements of each of the components in the DC-breaker. First of all, the choice of the semiconductor is important. There are a number of components available in the market, but typically they are optimized for fast switching applications like inverters rather than circuit breaker applications that only requires one single switching. Due to the high current and voltage ratings and the easy control, the IGBT seems to be the best choice among the commercially available components. Simulations on the mechanical switch show that there is an optimal combination of opening time and arc voltage of the to obtain a successful commutation into the semiconductor branch. The actuator is a key component since a relatively low increase in performance of the actuator drive circuit, significantly decreases the requirement of the other components in the DC-breaker. A significant part of the work has been put on the voltage transient during the turn-off of the semiconductor. As the current is forced into the varistor branch, the stray inductance in that loop will result in an over-voltage due to the high current derivative. A new type of snubber has been investigated using another varistor mounted close to the semiconductor. It has been shown that the function of the varistor snubber can be divided into two regions depending on the ratio between the snubber and the main varistor. If the ratio is high enough, the energy absorbed in the snubber varistor is only a few percent of the total energy. / Intresset för att använda likström i både transmission och distribution av elkraft har ökat tack vare en högre verkningsgrad och lägre förluster. En begränsande faktor för utbyggnad av likströmsnät är utvecklingen av brytare för likström. Svårigheten att bryta en likström jämfört med växelström är att det saknas en naturlig nollgenomgång där strömmen kan brytas. För att tvinga fram en nollgenomgång kan man använda en hybrid brytare som består av tre parallella grenar: en mekanisk switch, en gren med krafthalvledarkomponenter och en gren med en varistor. Hybridbrytaren bryter en ström i tre steg. I normalfallet leder den mekaniska kontakten strömmen för att hålla nere de elektriska förlusterna. När strömmen ska brytas öppnas den mekaniska kontakten och strömmen kommuteras över till krafthalvledargrenen. När krafthalvledaren stängs av, trycks strömmen över till den tredje grenen där varistorn begränsar spänningen över brytaren och absorberar den magnetiska energi som finns lagrad i nätet. Strömmen avtar och när systemet är avmagnetiserat når strömmen noll. Denna avhandling sammanfattar ett arbete att med hjälp av simuleringar och experiment få fram designparametrar för en sådan brytare. Flera simuleringsmodeller har av använts för att få fram designkriterier för de olika komponenterna i hybridbrytaren. Ett första steg är att välja krafthalvledarkomponent. Dessa komponenter är främst utvecklade för omvandling mellan lik- och växelström där de slås av och på i korta intervall. En brytartillämpning skiljer sig markant från detta eftersom strömmen bara behöver brytas enstaka gånger vilket ändrar kraven på komponenten. Enkelheten i att kontrollera komponenten tillsammans med dess höga ström- och spänningstålighet gör IGBTn till det bästa valet bland de kommersiellt tillgängliga komponenterna. Simuleringar visar att en optimal design av den mekaniska switchen är en kombination av snabbhet och ljusbågsspänning. En nyckelkomponent är den snabba aktuatorn som driver switchen. En relativt liten förbättring av drivkretsen kan leda till minskade krav och därmed kostnader på övriga komponenter i brytaren. En stor del av arbetet har lagts på att studera den transienta överspänningen då krafthalvledarkomponenten bryter strömmen. Den höga strömderivatan medför att även små ströinduktanser leder till relativt stora överspänningar som riskerar att skada brytaren. En ny typ av snubberkrets, bestående av en mindre varistor som monteras nära krafthalvledaren, har föreslagits. På detta sätt separeras överspänningsskyddet från absorptionen av den magnetiska energin. Experiment och simuleringar visar att om spänningsförhållandet mellan de två varistorerna är tillräckligt stort absorberas endast ett par procent av energin i snubbern. / <p>QC 20150420</p>

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With the proliferation of residential-scale renewable energy sources and DC loads, it has become attractive to use residential DC electrical system that could offer benefits over the legacy residential AC electrical system. The Hybrid AC/DC house provides a sustainable alternative to preexisting residential electrical system by having both AC and DC buses. The DC bus facilitates the connection from DC sources to DC loads, whereas the AC bus interfaces AC sources to AC loads. The study develops the equations to calculate losses based on a model consisting of four main components: Multiple-Input Single-Output (MISO) converter, AC-DC converter, inverter, and DC-DC converter. Parameters such as AC and DC bus voltages, load consumption, and number of AC and DC branches were used to construct multiple scenarios and evaluate efficiency. Results of the study show that the Hybrid AC/DC house displays higher efficiencies than when the house has AC only sources with higher DC load consumption. Similarly, the Hybrid AC/DC house has better efficiency than when the house has DC only sources under higher AC load consumption. For the DC bus, results of the study further indicate that the higher DC voltage level yields better efficiency than those obtained from lower DC voltages.