44 research outputs found

    Non-Linear Inductors Characterization in Real Operating Conditions for Power Density Optimization in SMPS

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    The exploitation of power inductors outside their linear region in switching converters can be achieved by raising the current until a decrease in the inductance can be noticed. This allows using a smaller magnetic core, increasing the power density of the converter. On the other hand, a detailed description of the magnetization curve including the temperature is required. Since this information is often not included in the inductor’s datasheets, this paper shows how to identify the behavior of an inductor when it is operated up to saturation and its temperature rises. In order to characterize the inductor in real operating conditions, a dedicated measurement rig was developed. It consists of a switching converter that encompasses the inductor under test and is controlled by a virtual instrument developed in LabVIEW. The characterization system was tested by retrieving the inductance and the magnetization curves vs. current for two commercial inductors at core temperatures up to 105 °C. The magnetic core was then characterized by the saturation current vs. inductance, obtaining an expression for the whole family of inductors sharing the same core. Finally, we experimentally analyzed the thermal transient of the inductors in operating conditions, confirming the fundamental role of the temperature in changing the current profiles and the core saturation condition

    Wind Power

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    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

    Electromagnetic Interference and Compatibility

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    Recent progress in the fields of Electrical and Electronic Engineering has created new application scenarios and new Electromagnetic Compatibility (EMC) challenges, along with novel tools and methodologies to address them. This volume, which collects the contributions published in the “Electromagnetic Interference and Compatibility” Special Issue of MDPI Electronics, provides a vivid picture of current research trends and new developments in the rapidly evolving, broad area of EMC, including contributions on EMC issues in digital communications, power electronics, and analog integrated circuits and sensors, along with signal and power integrity and electromagnetic interference (EMI) suppression properties of materials

    Single Conversion stage AMplifier - SICAM

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    Thermal and electro-thermal modeling of electronic devices and systems for high-power and high-frequency applications

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    Questo lavoro è incentrato sulla modellazione termica ed elettro-termica di dispositivi elettronici per applicazioni ad alta potenza ed alta frequenza. Quattro argomenti principali vengono affrontati: 1) il metodo agli Elementi Finiti (FEM) viene impiegato per studiare gli aspetti termici e fluido-termo-dinamici in alimentatori di potenza progettati per funzionare, con vincoli termici stringenti, in esperimenti di Fisica delle Alte Energie. 2) Un’ampia analisi è stata effettuata riguardo alla modellazione auto-consistente, elettro-termica a grande segnale di dispositivi elettronici, con la creazione di modelli termici dinamici, non-lineari, a parametri concentrati (costruiti con resistenze e capacità termiche), che si possono utilizzare con simulatori circuitali in maniera tale da poter essere accoppiati in modo auto-consistente con modelli (tipo SPICE) elettro-termici, a grande segnale dei dispositivi elettronici (HEMTs, MOSFETs). Questi modelli termici a parametri concentrati sono costruiti basandosi sulla struttura fisica del dispositivo, senza parametri di fitting, e sono stati confrontati con modelli FEM equivalenti (che invece non possono essere usati in simulatori circuitali assieme a modelli elettrotermici dei componenti), con eccellente accordo tra i due modelli. Quando l’approccio fisico non si può utilizzare, un metodo empirico per ricavare una rete dinamica compatta tipo Foster viene illustrato. 3) Il progetto di un banco di misura della temperatura su componenti integrati mediante tecnica di termo-riflettanza (ad alta risoluzione spaziale) viene illustrato. 4) Il progetto di un banco elettronico per la generazione di impulsi ad alta tensione (kV), con durata dell’ordine dei nanosecondi, da utilizzarsi in applicazioni biomedicali, assieme alla costruzione ed al collaudo di alcune sue parti, vengono illustrati.This work is focused on the thermal and electro-thermal modeling of electronic devices for high-power and high-frequency applications. This work covers four main topics: 1) the Finite Element Method (FEM) is used to study thermal and fluid-thermal aspects in power supplies, designed to meet stringent thermal constraints, to be used in High-Energy Physics Experiments. 2) An extensive analysis has been carried out about the self-consistent, electro-thermal large-signal modeling of electron devices, with the creation of non-linear, dynamic lumped-element (LE) thermal models (made of thermal resistances and thermal capacitances) suitable to insertion into circuit CAD tools, to be self-consistently coupled with large-signal, electro-thermal SPICE-like models of electron devices (HEMTs, MOSFETs). These LE thermal models are built in a physics-based way, and they were found to be in excellent agreement with Finite Element models (which, conversely, do not lend themselves to insertion into circuit-CAD tools), without using fitting parameters. When the physics-based approach is not suitable, an empirical approach to the creation of compact Foster dynamic LE models is shown. 3) The design of a bench for carrying out high-spatial resolution temperature measurements (on integrated components), using the thermo-reflectance technique, is illustrated. 4) The design of an electronic bench capable of generating high-voltage (kV), nano-second time duration pulses for biomedical applications is described, as well as the manufacturing and the assembly of some parts

    High-Performance Isolated Bidirectional DC-DC Converter

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    Conversores DC-DC bidireccionais têm vindo a ganhar atenção na área da eletrónica de potência devido ao aumento da necessidade de um fluxo de potência controlado entre dois barramentos DC. Aplicações típicas podem ser facilmente listadas, indo desde unidades de produção de energia renovável até veículos elétricos e híbridos. Estes conversores podem apresentar funcionalidades como elevada densidade energética e performance, assim como isolamento galvânico entre cada porto. Desta forma, a AddVolt requisitou que tal conversor fosse incluído na sua solução de travagem regenerativa. Com esta dissertação, um conversor DC-DC bidireccional e isolado é proposto, sendo que todos os aspetos desde revisão bibliográfica, modelação, design, simulação, implementação, teste e validação são abrangidos. Um conversor Dual-Active Bridge (DAB) de média potência e alta frequência é a topologia escolhida. Após validação de quer a topologia como a malha de controlo desenhada num ambiente computacional, um protótipo experimental é assemblado e testado com sucesso. O isolamento galvânico é garantido e atingido através de um transformador de alta frequência desenhado e enrolado pelo autor.Bidirectional DC-DC converters have been gaining attention in the field of power electronics due to the increasing need of a controlled power flow between two DC buses. Typical applications can be easily listed, ranging from renewable energy production units to electric and hybrid vehicles. Such converters can feature characteristics as high power density and performance as well as isolation between each port. As a result, AddVolt has commissioned that such a converter should be included in its regenerative breaking solution. Within this dissertation, a bidirectional isolated DC-DC converter is proposed, and all aspects from literature review, modelling, design, simulation, implementation, testing and validation are deeply covered. A medium-power high frequency Dual-Active Bridge (DAB) converter is the chosen topology. After validation of both the topology and control structure in a computational environment, an experimental prototype is assembled and successfully tested. Galvanic isolation is granted and achieved by a self-designed and in-house wound high frequency transformer

    Steady state load models for power system analysis

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    The last full review of load models used for power system studies occurred in the 1980s. Since then, new types of loads have been introduced and system load mix has changed considerably. The examples of newly introduced loads include drive-controlled motors, low energy consumption light sources and other modern power electronic loads. Their numbers have been steadily increasing in recent years, a trend which is expected to escalate. Accordingly, the majority of load models used in traditional power system studies are becoming outdated, as they are unable to accurately represent power demand characteristics of existing and future loads. Therefore, in order to accurately predict both active and non-active power demand characteristics of aggregated modern power system loads in different load sectors (e.g. residential, commercial or industrial), existing load models should be updated and new models developed. This thesis aims to fill this gap by developing individual, generic and aggregated steady state models of the most common loads in use today, as well as of those expected to show significant growth in the future. The component-based approach is adopted for load modelling, where individual load models are obtained in detailed simulations of physical devices. Whenever possible, the developed individual load models are validated by measurements. These detailed individual load models are then simplified and expressed as equivalent circuit and analytical models, which allowed the establishment of generic load models that can be easily aggregated. It should be noted that since all non-active power characteristics are correctly represented, the developed aggregated load models allow for a full harmonic analysis, which is not the case with the standard steady state load models. Therefore, the proposed load models form an extensive library of comprehensive load models that are suitable for use in multiple areas of power system research. Based on the results of research related to typical domestic/residential sector load mix, the newly developed load models are aggregated and then applied to a typical UK/Scotland distribution network. Considerable differences are seen between network characteristics of newly proposed and previously developed models. The voltage distortion of a typical distribution system bus is investigated, and it is shown that distortion of the system voltage is likely to increase significantly in the future. The results of the presented research also suggest that neglecting the harmonic characteristics from the set of general load attributes may introduce errors in standard load flow studies

    An Exploration of Maximum Power Point Tracking Algorithms

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    This project investigated the performance of various solar maximum power point tracking algorithms on a single hardware platform. It also developed a low-cost hardware platform including a rudimentary solar cell emulator circuit and a maximum power point tracker circuit to test these algorithms. Additionally, the project covered the development of the two software algorithms that were tested in the project: the ”Sweep” algorithm and the ”Perturb and Observe” algorithm

    Improving Sound Systems by Electrical Means

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