Stratégies de commande numérique pour un convertisseur DC/DC SEPIC en vue de l intégration

L utilisation des alimentations à découpage (SMPSs : switched mode power supplies) est à présent largement répandue dans des systèmes embarqués en raison de leur rendement. Les exigences technologiques de ces systèmes nécessitent simultanément une très bonne régulation de tension et une forte compacité des composants. SEPIC (Single-Ended Primary Inductor Converter) est un convertisseur à découpage DC/DC qui possède plusieurs avantages par rapport à d autres convertisseurs de structure classique. Du fait de son ordre élevé et de sa forte non linéarité, il reste encore peu exploité. L objectif de ce travail est d une part le développement des stratégies de commande performantes pour un convertisseur SEPIC et d autre part l implémentation efficace des algorithmes de commande développés pour des applications embarquées (FPGA, ASIC) où les contraintes de surface silicium et le facteur de réduction des pertes sont importantes. Pour ce faire, deux commandes non linéaires et deux observateurs augmentés (observateurs d état et de charge) sont exploités : une commande et un observateur fondés sur le principe de mode de glissement, une commande prédictive et un observateur de Kalman étendu. L implémentation des deux lois de commande et l observateur de Kalman étendu sont implémentés sur FPGA. Une modulation de largeur d impulsion (MLI) numérique à 11-bit de résolution a été développée en associant une technique de modulation - de 4-bit, un DCM (Digital Clock Management) segmenté et déphasé de 4-bit, et un compteur-comparateur de 3-bit. L ensemble des approches proposées sont validées expérimentalement et constitue une bonne base pour l intégration des convertisseurs à découpage dans les alimentations embarquées.The use of SMPS (Switched mode power supply) in embedded systems is continuously increasing. The technological requirements of these systems include simultaneously a very good voltage regulation and a strong compactness of components. SEPIC ( Single-Ended Primary Inductor Converter) is a DC/DC switching converter which possesses several advantages with regard to the other classical converters. Due to the difficulty in control of its 4th-order and non linear property, it is still not well-exploited. The objective of this work is the development of successful strategies of control for a SEPIC converter on one hand and on the other hand the effective implementation of the control algorithm developed for embedded applications (FPGA, ASIC) where the constraints of Silicon surface and the loss reduction factor are important. To do it, two non linear controls and two observers of states and load have been studied: a control and an observer based on the principle of sliding mode, a deadbeat predictive control and an Extended Kalman observer. The implementation of both control laws and the Extended Kalman observer are implemented in FPGA. An 11-bit digital PWM has been developed by combining a 4-bit - modulation, a 4-bit segmented DCM (Digital Clock Management) phase-shift and a 3-bit counter-comparator. All the proposed approaches are experimentally validated and constitute a good base for the integration of embedded switching mode convertersVILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

Power Converters in Power Electronics

In recent years, power converters have played an important role in power electronics technology for different applications, such as renewable energy systems, electric vehicles, pulsed power generation, and biomedical sciences. Power converters, in the realm of power electronics, are becoming essential for generating electrical power energy in various ways. This Special Issue focuses on the development of novel power converter topologies in power electronics. The topics of interest include, but are not limited to: Z-source converters; multilevel power converter topologies; switched-capacitor-based power converters; power converters for battery management systems; power converters in wireless power transfer techniques; the reliability of power conversion systems; and modulation techniques for advanced power converters

Advances in Rotating Electric Machines

It is difficult to imagine a modern society without rotating electric machines. Their use has been increasing not only in the traditional fields of application but also in more contemporary fields, including renewable energy conversion systems, electric aircraft, aerospace, electric vehicles, unmanned propulsion systems, robotics, etc. This has contributed to advances in the materials, design methodologies, modeling tools, and manufacturing processes of current electric machines, which are characterized by high compactness, low weight, high power density, high torque density, and high reliability. On the other hand, the growing use of electric machines and drives in more critical applications has pushed forward the research in the area of condition monitoring and fault tolerance, leading to the development of more reliable diagnostic techniques and more fault-tolerant machines. This book presents and disseminates the most recent advances related to the theory, design, modeling, application, control, and condition monitoring of all types of rotating electric machines

Innovative Digital dc-dc Architectures for High-Frequency High-Efficiency Applications

The new generation of automotive controllers requires a space-constrained and high-efficiency step-down architecture. Hence, recently a potential alternative for the conventional step-down topologies is highly demanded. The new architecture should meet the high power density, high efficiency, wide operating ranges, high EMI capabilities, and low-cost requirements. This thesis, developed at the University of Padova and sponsored by Infineon Technologies, aims at investigating potential candidate topologies for automotive step-down conversion capable of eliminating or offsetting some of the common shortcomings of conventional solutions currently in use. Many research effort is paid for the soft switching quasi-resonant topologies in order to miniaturize the passive components through the switching frequency increase. However, the variable switching frequency, increased components count, and narrow operating ranges prevent the wide adoption of the quasi-resonant topologies in the target application. The first objective of this project is to investigate the quasi-resonant buck converter topology in order to stand on the limitations and operating conditions boundaries of such topology. The digital efficiency optimization technique, which is developed in this work, extends the operating ranges in addition to reduce operating frequency variations. On the other hand, the multilevel hybrid topologies are potentially able to meet the aforementioned requirements. By multiplying ripple frequency and fractioning voltage across the switching node the multilevel topologies have the direct advantage of reduced passive components. Moreover, multilevel topologies have many other attractive features include reduced MOSFET voltage rating, fast transient response, a Buck-like wide range voltage conversion ratio, and improved efficiency. These features candidate the multilevel topologies, in particular, the three-level flying-capacitor converter, as an innovative alternative for the conventional topologies for the target application. Accordingly, the three-level flying-capacitor converter (3LFC) is investigated as a second objective for this project. Flying-capacitor (FC) voltage balancing in such topology is quite challenging. The 3LFC under valley current mode control shows an interesting performance, where the FC voltage is self-balanced. In this work, the stability of the converter under valley and peak current mode control is studied and a simplified stability criterion is proposed. The proposed criterion address both current loop static stability and FC voltage stability. The valley current mode modulator results to be inherently stable as soon as the current static instability is compensated with an external ramp. On contrary, the FC voltage in peak current mode control (P-CMC) will never be balanced unless the converter operated with relatively high static peak-to-peak inductor current ripple. Since P-CMC has an inherent over-current protection feature, P-CMC based architectures are widely used in the industrial applications. However, in practice the peak current controlled three-level converter is inherently unstable. Consequently, the instability of the P-CMC 3LFC is addressed. A sensorless stabilizing approach, with two implementation methodologies, is developed in this work. The proposed technique eliminates the instability associated with the FC voltage runaway, in addition to FC voltage self-balancing. Moreover, the proposed methodology offers reduced size, less complexity, and input voltage independent operation. Besides, the proposed approach can be extended to system with a higher number of voltage levels with minimal hardware complexity. The proposed techniques and methodologies in this work are validated using simulation models and experimentally. Finally, in the conclusions the results of the Ph.D. activity are summarized and recommendations for the further development are outlined

Design and Control of Power Converters 2019

In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc

Isolated Single-stage Power Electronic Building Blocks Using Medium Voltage Series-stacked Wide-bandgap Switches

The demand for efficient power conversion systems that can process the energy at high power and voltage levels is increasing every day. These systems are to be used in microgrid applications. Wide-bandgap semiconductor devices (i.e. Silicon Carbide (SiC) and Gallium Nitride (GaN) devices) are very promising candidates due to their lower conduction and switching losses compared to the state-of-the-art Silicon (Si) devices. The main challenge for these devices is that their breakdown voltages are relatively lower compared to their Si counterpart. In addition, the high frequency operation of the wide-bandgap devices are impeded in many cases by the magnetic core losses of the magnetic coupling components (i.e. coupled inductors and/or high frequency transformers) utilized in the power converter circuit. Six new dc-dc converter topologies are propose. The converters have reduced voltage stresses on the switches. Three of them are unidirectional step-up converters with universal input voltage which make them excellent candidates for photovoltaic and fuel cell applications. The other three converters are bidirectional dc-dc converters with wide voltage conversion ratios. These converters are very good candidates for the applications that require bidirectional power flow capability. In addition, the wide voltage conversion ratios of these converters can be utilized for applications such as energy storage systems with wide voltage swings