ADVANCED TOPOLOGIES OF HIGH-VOLTAGE-GAIN DC-DC BOOST CONVERTERS FOR RENEWABLE ENERGY APPLICATIONS by AHMAD SAEED Y. ALZAHRANI--MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY--DOCTOR OF PHILOSOPHY in ELECTRICAL ENGINEERING 2018

 CONVERTERS FOR RENEWABLE ENERGY APPLICATIONS by AHMAD SAEED Y. ALZAHRANI MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY 

 In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in ELECTRICAL ENGINEERING- 2018 

 ABSTRACT

 This dissertation proposes several advanced power electronic converters that are suitable for integrating low-voltage dc input sources, such as photovoltaic (PV) solar panels, to a high voltage dc bus in a 200 − 960 V dc distribution system. The proposed converters operate in the continuous conduction mode (CCM) and offer desirable features such as lowvoltage stresses on components, continuous input currents, and the ability to integrate several independent dc input sources. First, a family of scalable interleaved boost converters with voltage multiplier cells (VMC) is introduced. Several possible combinations of Dickson and Cockcroft-Walton VMCs are demonstrated and compared in terms of the voltage gain, number of components, and input current sharing. This dissertation also presents a novel VMC structure called Bi-fold Dickson. The novel VMC offers equal current sharing between phases regardless of the number of stages, voltage ripple cancellation at each stage, and does not require an output diode. A family of high-voltage-gain multilevel boost converters is presented, with detailed example of the hybrid flyback and three-level boost converter. In this family, the effective frequency seen by the magnetic element is multiple times the switching frequency, and therefore smaller magnetic devices can be used. Theory of operations, steady-state analysis, component selections, simulation, and efficiency analysis are included for each proposed converter. The operation of the proposed converters was further verified with 80 − 200 W hardware prototypes.

LINK: https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=3721&context=doctoral_dissertations

Design and Control Methodology for Improved Operation of a HV Bipolar Hybrid Switched Capacitor Converter J. Delhotal, J. Richards, J. Stewart, J. Neely, J. Flicker, R. Brocato, L. Rashkin Sandia National Laboratories Albuquerque, New Mexico, USA

Design and Control Methodology for Improved Operation of a HV Bipolar Hybrid Switched Capacitor Converter J. Delhotal, J. Richards, J. Stewart, J. Neely, J. Flicker, R. Brocato, L. Rashkin Sandia National Laboratories Albuquerque, New Mexico, USA Email: jneely@sandia.gov Jane Lehr University of New Mexico Albuquerque, New Mexico, USA 

 Abstract— In this work, a novel dc-dc converter topology, an adaptation of the Hybrid Switched Capacitor Circuit (HSCC), is considered for use in high-gain, high voltage applications that also require high efficiency and superior power density. In particular, a bipolar HSCC design is described, and a candidate control methodology is set forth and developed analytically. The converter performance is demonstrated to be consistent with analysis. In addition, the converter is demonstrated to step 460V up to 8.63 kV (gain of 19) at 3.63 kW and nearly 97.0% efficiency. 

LINK VIEW FULL TEXT IN WEB:

https://www.osti.gov/servlets/purl/1473752

DESIGN AND DEVELOPMENT OF POWER PROCESSING UNITS FOR APPLICATIONS IN ELECTRICALLY-PROPELLED SATELLITE SYSTEMS by KARTIKEYA JAYADURGA PRASAD VEERAMRAJU---Requirements for the Degree MASTER OF SCIENCE in ELECTRICAL ENGINEERING--MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY-

 

DESIGN AND DEVELOPMENT OF POWER PROCESSING UNITS FOR APPLICATIONS IN ELECTRICALLY-PROPELLED SATELLITE SYSTEMS by KARTIKEYA JAYADURGA PRASAD VEERAMRAJU

 A THESIS Presented to the Graduate Faculty of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE in ELECTRICAL ENGINEERING 2020 

 ABSTRACT 

Electrospray technology provides a way to ionize specialized liquids by applying high voltages across a sharp porous tip and a metallic mesh. This technology is widely used in the field of mass spectroscopy for generating ions for testing purposes. The dawn of nano-satellites posed new challenges in the miniaturization of many conventional satellite sub-systems. One significant challenge faced in such a process was the miniaturization of the propulsion system. Electrosprays have started to find their application in the field of Aerospace Engineering and now are formally known as Electrospray Thrusters. These thrusters provide high specific impulse and are attractive substitutes to conventional gas propelled thrusters as they can be scaled down in size and can also provide extended mission times. Some of the new challenges faced in such applications are the generation of high voltages from a lowvoltage onboard battery, grounding, spacecraft charging, clearance, and reliability issues for long term usage. In this work, a complete design process is developed for the realization of such high voltages suitable for interfacing with an electrospray thruster. Simulation models for a new type of converter are assessed, and its feasibility is discussed. A hardware prototype is implemented, and the practical results are assessed. An analysis of the converter is presented, and the semiconductor and passive components are selected. Magnetic components are designed based on the analysis. Parallels are drawn between the theoretical and prototype model of the concept converter. Finally, the firmware of the converter is explained, and the communication protocol of the PPU is delineated. As the boards designed for the converter have to sustain high voltages and reliably operate in unfavorable environments, special PCB layout considerations must be used, which also forces a designer to look for various other materials for the PCB fabrication.

 LINK VIEW FULL TEXT IN WEB:

https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=8938&context=masters_theses

Characterization and Design of HighSwitching Speed Capability of GaN Power Devices in a 3-Phase Inverter-Rémi PERRIN-THESE de DOCTORAT DE L’UNIVERSITE DE LYON opérée au sein de Laboratoire AMPERE

 

Characterization and design of the switching frequency rise of a 3-phase inverter with GaN transistors by Rémi Perrin

 Abstract 

The French industrial project MEGaN aims to develop a power module based on HEMT compost in GaN. One of the industrial applications concerns aeronautics with a high constraint in galvanic isolation (> 100 kV / s) and in ambient temperature (200 ° C). The thesis work was focused on a power module brick (650 V 30 A inverter arm). The objective is to achieve a prototype of thin form factor, 30 cm2 and embedding all the driver functions, driver power supply, bus capacity and phase current sensor. This objective implies high energy efficiency, and respect for galvanic insulation while the surface stress is high. The manuscript, in addition to the state of the art relating to the power module and in particular that based on GaN HEMT transistor, discusses a micro-transformer-based control signal isolation solution. Micro-transformer prototypes were characterized and aged for 3000 hours to assess the robustness of the solution. The work contributed to the characterization of several GaN components in order to mature models for circuit simulation of converter topology. Within the MEGaN collaborative work, our contribution did not concern the design of the integrated circuit (grid driver), while having participated in the validation of the specifications, but a power supply strategy for the grid driver. A first isolated power supply proposal for the gate driver favored the use of low-voltage GaN components. The resonant flyback topology with clamp makes it possible to get the most out of these GaN components but poses the constraint of the power transformer. Several technologies for the realization of the transformer have been validated experimentally and in particular an original proposal for the burial of the magnetic component within a high-temperature polymer substrate. In particular, an inexpensive manufacturing process makes it possible to obtain a reliable device (1000 h of cycling between - 55; + 200 ° C), with an intrinsic efficiency of 88% for 2 W transferred. The parasitic insulation capacity is reduced compared to previous prototypes. Two prototypes of highly integrated power supplies use either low voltage GaN transistors (2.4 MHz, 2 W, 74%, 6 cm2), or a dedicated integrated circuit in CMOS SOI technology, designed for the application (1.2 MHz, 2 W, 77%, 8.5 cm2). The manuscript then proposes an integrable solution for measuring the phase current of the bridge arm, based on a magnetoresistance. The experimental comparison with respect to a shunt resistance solution. Finally, two converter prototypes are described, one of which has been the subject of an experimental validation demonstrating reduced switching losses.

VIEW FULL TEXT :http://theses.insa-lyon.fr/publication/2017LYSEI001/these.pdf

Design and characterization of a three-phase current source inverter using 1.7kV SiC power devices for photovoltaic applications-Présentée par Luís Gabriel ALVES RODRIGUES Laboratoire de Génie Electrique de Grenoble dans l'École Doctorale Electronique, Electrotechnique, Automatique et Traitement du Signal-

 

Abstract 

Classically, the energy conversion architecture found in photovoltaic (PV) power plants includes solar arrays delivering a maximum voltage of 1kV followed by a step-up chopper connected to a three-phase Voltage Source Inverter. This multistage conversion system (DC/DC + DC/AC) is then connected to the medium-voltage grid through a low-voltage/medium-voltage transformer. In order to simplify the PV systems, this research work focuses on the study and implementation of a DC/AC topology employing a single power processing stage: the three-phase Current Source Inverter (CSI). To deal with the inconvenient of high conduction losses when implementing this topology, wide-bandgap Silicon Carbide (SiC) semiconductors are used, allowing to efficiently convert energy while keeping a relatively high switching frequency. Nonetheless, since the available power semiconductor modules on the market are not compatible with the CSI, a novel 1.7kV SiC-based voltage bidirectional module is developed in the context of this thesis. Hence, the dynamic characterization of the new SiC device is carried out and serves as the basis for the design of a 60kW CSI prototype. Finally, the inverter efficiency is evaluated at nominal operating conditions, employing both a calorimetric and electrical methods. The obtained results confirm the CSI ability to operate efficiently at high switching frequencies (η>98.5% @60kHz). The originality of this work lies mainly in the design, characterization and implementation of the new 1.7kV full-SiC power module adapted to the CSI topology. Keywords: Power electronics, DC/AC converters, Current Source Inverter (CSI).

VIEW FULL TEXT : https://tel.archives-ouvertes.fr/tel-02476261/document