POWER ELECTRONICS SOLUTIONS FOR UNINTERRUPTED POWER SUPPLY AND GRID-TIE INVERTERS A Thesis Submitted to the Faculty of Purdue University by Omar N. Nezamuddin

POWER ELECTRONICS SOLUTIONS FOR UNINTERRUPTED POWER SUPPLY AND GRID-TIE INVERTERS A Thesis Submitted to the Faculty of Purdue University by Omar N. Nezamuddin Master of Science in Electrical and Computer Engineering

 ABSTRACT
 Nezamuddin, Omar N. MSECE, Purdue University, December 2014. Power Elec-tronics Solutions for Uninterrupted Power Supply and Grid-Tie Inverters.
 Major Professor: Euzeli dos Santos Jr.
 This thesis proposes two new topologies for Uninterrupted Power Supply (UPS), and a grid-tie microinverter. The rst topic will discuss an on-line transformerless UPS system based on the integrated power electronics converters that is able to con- trol the input power factor, charge the battery, and guarantee backup operation of the system. The main advantages of the proposed UPS are active power factor correc- tion (PFC) without the need of a complex control scheme, and integrated functions of the battery charger circuit and PFC with only three power switches. Operation modes of the system and the PWM strategy is presented in detail. The second topic discussed is of a proposed circuitry for a single-phase back-to-back converter for UPS applications. The main advantages of this topology is higher number of levels at the recti er side, less number of power switches, and no need for a boost inductor at the input side of the converter. The last topic discussed is of a proposed patent pending microinverter. This topic was a project funded by the National Science Foundation, and its aim was to help commercialize the research. This project proposes a solution for a solar inverter called Delta Microinverter that allows easier and faster installation as well as power conversion with higher efficiency. Delta Microinverters innovation is found in its patent-pending shape and in its patent-pending circuitry, i.e., electronics mounted inside of the Delta Microinverter. The Delta Microinverters shape has a housing con gured for rapid mounting using a single fastener and its power electron- ics con guration offers an optimized relationship between the number of levels and number of power switches.
LINK
https://core.ac.uk/reader/81633520

IMPLEMENTATION OF ONLINE IMPEDANCE MEASUREMENT SETUP FOR THREE-PHASE GRID-CONNECTED INVERTERS - TOMMI REINIKKA-Tampere University of Technology Master of Science Thesis

TOMMI REINIKKA: Implementation of online impedance measurement setup for three-phase grid-connected inverters Tampere University of Technology Master of Science Thesis,March 2017

 ABSTRACT
 In the thesis a fast method for measuring the output impedance of a grid-connected inverter by broadband excitation and cross-correlation techniques is studied. The study is made for determining stability of a grid-connected power electronics system by using impedance based stability criterion. The goal of this work is to build a test bench for inverter experiments and to verify the accuracy of the used measurement technique. Renewable power generation, such as solar and wind power, require a way to synchronize and connect to the grid. This is usually done by using grid-parallel inverters. However impedance mismatch between the grid and the interfacing inverter may cause the inverter to generate harmonic resonances. The resonance problems can be analyzed and prevented using analytical inverter models or measured frequency responses. In this thesis pseudo-random sequences and grid emulator are used to measure the inverter output impedance at a high frequency band. The experiments were done by injecting the pseudo-random binary sequence signal into the grid voltage reference. The grid voltages and currents were measured and used to calculate the inverter's frequency response with voltage as the input and current as the output. The measurements were veri ed by comparing them to theoretical values.

LINK
https://core.ac.uk/reader/80539115

Analysis of the Structures of Switching Power Supplies in the Environment OrCAD/PSpice By David Krajc-Technical University of Ostrava

Analysis of the Structures of Switching Power Supplies in the Environment OrCAD/PSpice By David Krajc Technical University of Ostrava

Abstract The thesis deals with switching power supplies and theirs characteristics. At the beginning of this thesis is a division of switching power supplies, describes the principles function and the basic characteristics circuits. They are then made suggestions of circuit components for Forward, Flyback and Push-Pull switching power supply. On the basis of simulation models are made in the environment OrCAD / PSpice subject for Power Semiconductor Systems II. At the end of the thesis simulated results are comparing with theoretical assumptions.
 LINK ORIGINAL
https://core.ac.uk/reader/84391389

CONVERTISSEURS DC/DC A BASE DE HFETs GaN POUR APPLICATIONS SPATIALES Présentée et soutenue par : M. GUILLAUME DELAMARE Ecole doctorale : Génie Electrique, Electronique, Télécommunications (GEET) DOCTORAT DE L'UNIVERSITÉ DE TOULOUSE

CONVERTISSEURS DC/DC A BASE DE HFETs GaN POUR APPLICATIONS SPATIALES Présentée et soutenue par : M. GUILLAUME DELAMARE Ecole doctorale : Génie Electrique, Electronique, Télécommunications (GEET) 

 Abstract Improving the compactness and efficiency of switching converters is a central issue in power electronics ; even more so in satellites where every gram and every watt counts. Each of the many radio-frequency emitters and receivers onboard telecommunications satellites need to be powered by various voltages, converted in an isolated way from the main power distribution bus. Due to the strong thermal, reliability and radiation hardness constraints applying to electronic components in space applications, available degrees of freedom for improvement of power supplies are limited - at least with current qualified semiconductor technologies (which are both expensive and far behind state-of-the-art performance). The recent commercialization of gallium nitride (GaN) normally-off power transistors, having superior electrical characteristics compared to the best silicon power MOSFET, is promising on that regard. Indeed, their intrinsic radiation hardness seems to allow their use in space-grade converters. The aim of this work is the evaluation of how this technology can help improve the design of isolated DC/DC power supplies for typical hardware units of telecommunications satellite payloads. Operation at higher switching frequencies with these better performing components should, in principle, reduce converters’ footprint while keeping the same (or better) efficiency level and still obeying each application’s specific requirements. The accuracy of this hypothesis as well as the most adequate implementation architecture have been explored for the low power supply of a RF receiver, including realization and comparison of several demonstration boards. In order to approach higher power converters, a theoretical and experiment study of switching losses in GaN transistor bridge legs has been performed. A performance computation software has been developed in Python and used to identify the global optimum of the design of a Dual Active Bridge converter for a power RF amplifier (250W DC). A prototype board has been built and demonstrated the interest of both the topology and GaN devices in this application, while clearly showing that high-frequency losses in magnetic components dominate total converter loss. This last issue happens to be the main limitation of the approach - precious to the engineer - of optimum design by computation : currently existing models for power loss estimation in magnetic elements are not satisfactory to predict performances of this type of converter.

LINK ORIGINAL
https://core.ac.uk/download/pdf/78385176.pdf

Couplage des systèmes photovoltaïques et des véhicules électriques au réseau Problèmes et solutions -Van Linh Nguyen- Energie électrique.Université de Grenoble-Thése

Couplage des systèmes photovoltaïques et des véhicules électriques au réseau Problèmes et solutions Van Linh Nguyen -Energie électrique-Université de Grenoble

LINK ORIGINAL 
https://hal.archives-ouvertes.fr/tel-01115864/document