Um die anderen Arten von Veröffentlichungen zu diesem Thema anzuzeigen, folgen Sie diesem Link: Multi-phase DC/DC converter.
Dissertationen zum Thema „Multi-phase DC/DC converter“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Dissertationen für die Forschung zum Thema "Multi-phase DC/DC converter" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Dissertationen für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
1
Qin, Ruiyang. „Study on Three-level DC/DC Converter with Coupled Inductors“. Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73169.
Der volle Inhalt der QuelleAnnotation:
High power multi-level converters are deemed as the mainstay power conversion technology for renewable energy systems including the battery storage system, PV farm and electrical vehicle charge station. This thesis is focused on the study of three-level DC/DC converter with multi-phase interleaved structure, with coupled and integrated magnetics to achieve high power density. The proposed interleaved phased legs offer the benefit of output current ripple reduction, while inversed coupled inductors can suppress the circulating current between phase legs. Compared with conventional non-interleaving three-level DC/DC converter with non-coupling inductors, both inductor current ripple and output current ripple are largely reduced by interleaving with inverse-coupled inductors.
Because of the non-linearity of the inductor coupling, the equivalent circuit model is developed for the proposed interleaving structure. The model identifies the existence of multiple equivalent inductances during one switching cycle. A combination of them determines the inductor current ripple and dynamics of the system. By virtue of inverse coupling and means of controlling the coupling coefficients, one can minimize the current ripple and the unwanted circulating current.
To further reduce the magnetic volume, the four inductors in two-phase three-level DC/DC converter are integrated into one common structure, incorporating the negative coupling effects. The integrated magnetic structure can effectively suppress the circulating current and reduce the inductor current ripple and it is easy to manufacture. This thesis provides an equivalent circuit model to facilitate the design optimization of the integrated system.
A prototype of integrated coupled inductors is assembled with nano-crystalline C-C core and powder block core. It is tested with both impedance analyzer and single pulse tester, to guarantee proper mutual inductance for inductor current ripple and output current ripple target. With a two-phase three-level DC/DC converter hardware, the concept of integrated coupled inductors is verified, showing its good performance in high-voltage, high-power conversion applications.Master of Science
2
Jacobs, Joseph [Verfasser]. „Multi-Phase Series Resonant DC-to-DC Converters / Joseph Jacobs“. Aachen : Shaker, 2006. http://d-nb.info/1166513211/34.
Der volle Inhalt der Quelle
3
Liu, Changrong. „A Novel High-Power High-Efficiency Three-Phase Phase-Shift DC/DC Converter for Fuel Cell Applications“. Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26048.
Der volle Inhalt der QuelleAnnotation:
Fuel cells are a clean, high-efficiency source for power generation. This innovative technology is going to penetrate all aspects in our life, from utility distributed power, transportation applications, down to power sources for portable devices such as laptop computer and cell phones. To enable the usage of fuel cell, developing power converters dedicated for fuel cells becomes imminent.
Currently, the full-bridge converter is the dominating topology in high power dc/dc applications. Although multiphase converters have been proposed, most of them are dealing with high input-voltage systems, and their device characteristic is not suitable for a low voltage source such as a fuel cell. For a high power fuel cell system, high voltage conversion ratios and high input currents are the major obstacles to achieving high-efficiency power conversions. This dissertation proposes a novel 3-phase 6-leg dc/dc power converter with transformer isolation to overcome these obstacles. Major features of the proposed converter include: (1) Increase converter power rating by paralleling phases, not by paralleling multiple devices; (2) Double the output voltage by transformer delta-wye connection, thus lowering the turns-ratio; (3) Reduce the size of output filter and input dc bus capacitor with interleaved control; (4) Achieve Zero-Voltage Zero-Current Switching (ZVZCS) over a wide load range without auxiliary circuitry. High conversion efficiency above 96% is verified with different measurement approaches in experiments.
This dissertation also presents the power stage and control design for the proposed converter. Control design guideline is provided and the design result is confirmed with both simulation and hardware experiments. When using the fuel cell for stationary utility power applications, a low-frequency ripple interaction was identified among fuel cell, dc/dc converter and dc/ac inverter. This low frequency ripple tends to not only damage the fuel cell, but also reduce the source capability. This dissertation also investigates the mechanism of ripple current propagation and exploits the solutions. A linearized ac model is derived and used to explain the ripple propagation. An active ripple reduction technique by the use of the current loop control is proposed. This active current loop control does not add extra converters or expensive energy storage components. Rather, it allows a reduction in capacitance because the ripple current flowing into the capacitor is substantially reduced, and less capacitance can be used while maintaining a clean dc bus voltage. The design process and guideline for the proposed control is suggested, and the effectiveness of this active control is validated by both simulation and experimental results.Ph. D.
4
Wallberg, Alexander. „Design and construction of a bidirectional DC/DC converter“. Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385240.
Der volle Inhalt der QuelleAnnotation:
A four quadrant general single-phase bi-directional DC/DC converter was designed and constructed for high effect systems. The target application for the DC/DC converter was to be used to transfer energy between different energy storages, a miniature DC power grid and the high voltage AC power city grid. The converter is capable of step-up and step-down operations in both directions i.e. it is bi-directional at varying voltage levels. Different DC/DC topologies were investigated, and thereafter simulations were performed in LTspice and Simulink to ensure its capabilities and functionalities. The result of the simulations was a two layered PI-regulator, controlling both the external DC-grid voltage and inductor current through the converter. Once a suitable topology and control strategy was found, a suitable power transistor investigated and a PCB driver card were developed with KiCad. The final converter is capable to seamlessly change between its four modes and controlling voltages up to 1200 V and currents up to 200 A.
5
Fan, Shixiong. „Current source DC/DC converter based multi-terminal DC wind energy conversion system“. Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=17007.
Der volle Inhalt der QuelleAnnotation:
Wind power energy conversion is growing rapidly in the world. There are two main wind farm types, namely ac grid-based and dc grid-based wind farms. The dc grid-based approach reduces the size and weight of the magnetic components and cables. In the dc system, the step-up dc/dc converter is the key component when interfacing the wind turbine to the ac grid, via its low/medium voltage generator. This thesis focuses on the control and design of a wind energy conversion system based on dc/dc current source converters. An optimized One-Power-Point method for maximum power tracking is proposed. It incorporates One-Power-Point control and Maximum Power Differential Voltage control to allow the wind turbine to extract more energy during rapid wind speed changes. A current output hard-switched full bridge converter and serial-parallel resonant converter with an intermediate high frequency transformer are investigated for interfacing wind turbines to a local dc grid. These converters are assessed and compared in terms of semiconductor stresses and losses. A new modified One-Power-Point control method is proposed for the dc/dc converter, which tracks the maximum power during wind speed changes. A design procedure for the serial-parallel resonant converter is presented, based on its characteristics specific to a wind energy conversion system (WECS). A current source dc/dc converter based multi-terminal dc WECS is presented, investigated, and simulated. A practical multi-terminal dc WECS verifies its feasibility and stability, using two dc current output wind turbine units. Furthermore, a coordinated de-loading control scheme for the current sourcing based WECS is proposed, to cater for ac grid demand changes. It combines pitch control, dc dumping chopper control, and dc/dc converter control, to safely and quickly establish de-loading control. Both simulation and experimental results verify the de-loading scheme.
6
Rezaee, Ali. „WIDE RANGE BI-DIRECTIONAL DC-DC CONVERTER“. Thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-41189.
Der volle Inhalt der QuelleAnnotation:
Bi-directional DC-DC converters are used for applications that require a flow of energy in two directions, while a wide range converter offer efficient operation over a wide range of input and output voltages. However, an efficient technology that is both bi-directional and Wide Input Wide Output (WIWO), currently, does not currently exist. To find a suitable topology, the work began by surveying the existing literature and when a potentially suitable solution was identified, it was evaluated via simulation. Using a wide range, unidirectional topology as the starting point, a converter topology was designed, capable of reconfiguring its transformer ratios by controlling the synchronization of its switches. By aiming to use soft switching in simulation, this topology was improved to reach 92\% efficiency in the forward mode and 95\% in the reverse mode of operation. Furthermore, a prototype of this converter was developed that reached 82\% efficiency. While this prototype requires a better controller, hardware optimization and testing for optimal performance, the proposed technology was verified via simulation to work as a WIWO converter that is also bi-directional.
7
Ward, Gillian Anne. „Design of a multi-kilowatt, high frequency, DC-DC converter“. Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274596.
Der volle Inhalt der Quelle
8
Gunawan, Tadeus. „Two-Phase Boost Converter“. DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/200.
Der volle Inhalt der QuelleAnnotation:
A boost converter is one of the most efficient techniques to step up DC input voltage to a higher needed DC output voltage. The boost converter has many possible applications, such as in a photovoltaic system, hybrid car and battery charger. The proposed prototype in this report is a proof of concept that a Two-Phase Boost Converter is a possible improvement topology to offer higher efficiency without compromising any advantages readily offered by a basic boost. The prototype is designed to be able to handle up to 200 watts of output power with an input of 36 volts and an output of 48 volts. This paper goes through step-by-step the calculation, design, build and test of a Two-Phase Boost Converter. Calculations found in this paper were done on Mathcad and the simulations were done on LTSpice and Pspice. These include converter’s efficiency and other measures of converter’s performance. Advantages, disadvantages as well as possible improvements of the proposed topology will be presented. Data collected and analyzed from the prototype were done on a bench test, not through an actual application.
9
Mazza, Luan Carlos dos Santos. „Single phase bidirectional DAB DC-DC converter based on three state switching cell“. Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14412.
Der volle Inhalt der QuelleAnnotation:
This work presented is DC-DC isolated ZVS Bidirectional Dual Active Bridge (DAB) single phase converter, based three-state switching cell is presented. The proposal is to apply it in photovoltaic systems with battery bank into smart networks. Basically the drive control is the duty cycle (D) of the switches and the Phase Shift (φ) of the fundamental tensions between the bridges. The gyrator modeling of the converter is presented, highlighting its natural operating characteristic as gyrator. Shows the qualitative and quantitative analysis of the converter, realizing the full study of the stages of operation of the topology and checking all sixteen regions of operation. To obtain the regions of soft-switching, the fundamental model is applied. The design procedure of the converter is presented, and the results of simulations. A 2kW prototype was developed, aimed at obtaining experimental results validate the theoretical analysisNeste trabalho à apresentado o conversor CC-CC ZVS isolado bidirecional Dual Active Bridge (DAB) monofÃsico, baseado na cÃlula de comutaÃÃo de trÃs estados. A proposta à aplicÃ-lo em sistemas fotovoltaicos com banco de baterias em redes inteligentes. Basicamente o controle do conversor consiste na razÃo cÃclica (D) dos interruptores e o Phase Shift (φ) entre as componentes fundamentais das tensÃes entre as pontes. A modelagem por gyrator do conversor à apresentada, destacando-se sua caracterÃstica natural de funcionamento como gyrator. Mostra-se a anÃlise qualitativa e quantitativa do conversor, realizando o estudo completo das etapas de operaÃÃo da topologia e verificando todas as dezesseis regiÃes de operaÃÃo. Para obtenÃÃo das regiÃes de comutaÃÃo suave, à aplicado o modelo fundamental. O procedimento de projeto do conversor à apresentado, alÃm dos resultados de simulaÃÃes. Um protÃtipo de 2 kW foi desenvolvido, visando a obtenÃÃo dos resultados experimentais e validando a anÃlise teÃrica.
10
Francisco, Venustiano Canales Abarca. „Novel DC/DC Converters For High-Power Distributed Power Systems“. Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/28612.
Der volle Inhalt der QuelleAnnotation:
One of the requirements for the next generation of power supplies for distributed power systems (DPSs) is to achieve high power density with high efficiency.
In the traditional front-end converter based on the two-stage approach for high-power three-phase DPSs, the DC-link voltage coming from the power factor correction (PFC) stage penalizes the second-stage DC/DC converter. This DC/DC converter not only has to meet the characteristics demanded by the load, but also must process energy with high efficiency, high reliability, high power density and low cost. To meet these requirements, approaches such as the series connection of converters and converters that reduce the voltage stress across the main devices have been proposed.
In order to improve the characteristics of these solutions, this dissertation proposes high-efficiency, high-density DC/DC converters for high-power high-voltage applications.
In the first part of the dissertation, a DC/DC converter based on a three-level structure and operated with pulse width modulation (PWM) phase-shift control is proposed. This new way to operate the three-level DC/DC converter allows soft-switching operation for the main devices. Zero-voltage switching (ZVS) and zero-voltage and zero-current switching (ZVZCS) soft-switching techniques are studied, analyzed and compared in order to improve the characteristics of the proposed converter. This results in a series of ZVS and ZVZCS three-level DC/DC converters for high-power high-voltage applications. In all cases, results from 6kW prototypes operating at 100 kHz are presented.
In addition, with the ultimate goal of improving the power density of the DC/DC converter, a study of several resonant DC/DC converters that can operate at higher switching frequencies is presented. From this study, a three-element ZVS three-level resonant converter for applications with wide input voltage and load variations is proposed. Experimental results at 745 kHz obtained without penalizing the efficiency of the PWM approaches are presented.
The second part of the dissertation proposes a quasi-integrated AC/DC three-phase converter that aims to reduce the complexity and cost of the traditional two-stage front-end converter. This converter improves the complexity/low-efficiency tradeoff characteristics evident in the two-stage approach and previous integrated converters. The principle of operation for the converter is analyzed and verified on a 3kW experimental prototype.Ph. D.
11
Mupambireyi, Ushindibaba. „Modelling, analysis and control of multi-phase electronically commutated DC machines : an enabling topology for DC converter fed networks“. Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/101516/.
Der volle Inhalt der QuelleAnnotation:
Multiphase electronically commutated dc machine is a new non-conventional machine and converter topology aimed at dc power generation and delivery systems. This thesis presents a detailed analysis of two multiphase electronically commutated dc machine topologies, firstly, the two level topology then the multilevel topology. Electronic current commutation processes in these topologies are analysed and electrical machine parameters that influence current commutation and the design of the electronic commutator are exposed. The behaviour of the power electronic commutator circuit is shown to be tightly coupled to that of the electrical machine connected to it and to be inductively dominated during current commutation. Performance, efficiency, footprint and cost are all affected by design considerations arising from the interaction of electronic commutator switching devices and electrical machine. Thus there is an incentive to ensure that the designs of power electronic commutator circuits and electrical machines are matched, allowing the requirements of the system as a whole to be satisfied. Since these machine and converter topologies depart from the conventional machine and converter topologies, an alternative modelling approach that lends itself well to modelling of the machine and its associated power electronics is presented. The models are used to evaluate the operational attributes of the machine and its associated electronic commutator power electronic circuit and the proposed control schemes. Results from two prototype laboratory drives built to practically access the viability and fully characterise the operational behavior of these topologies together with the simulation results are presented. Conclusions are drawn concerning the proposed topologies and their associated control strategies.
12
Mazumder, Sudip K. „Nonlinear Analysis and Control of Standalone, Parallel DC-DC, and Parallel Multi-Phase PWM Converters“. Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28690.
Der volle Inhalt der QuelleAnnotation:
Applications of distributed-power systems are on the rise. They are already used in telecommunication power supplies, aircraft and shipboard power-distribution systems, motor drives, plasma applications, and they are being considered for numerous other applications. The successful operation of these multi-converter systems relies heavily on a stable design. Conventional analyses of power converters are based on averaged models, which ignore the fast-scale instability and analyze the stability on a reduced-order manifold. As such, validity of the averaged models varies with the switching frequency even for the same topological structure.
The prevalent procedure for analyzing the stability of switching converters is based on linearized smooth averaged (small-signal) models. Yet there are systems (in active use) that yield a non-smooth averaged model. Even for systems for which smooth averaged models are realizable, small-signal analyses of the nominal solution/orbit do not provide anything about three important characteristics: region of attraction of the nominal solution, dependence of the converter dynamics on the initial conditions of the states, and the post-instability dynamics. As such, converters designed based on small-signal analyses may be conservative. In addition, linear controllers based on such analysis may not be robust and optimal. Clearly, there is a need to analyze the stability of power converters from a different perspective and design nonlinear controllers for such hybrid systems.
In this Dissertation, using bifurcation analysis and Lyapunov's method, we analyze the stability and dynamics of some of the building blocks of distributed-power systems, namely standalone, integrated, and parallel converters. Using analytical and experimental results, we show some of the differences between the conventional and new approaches for stability analyses of switching converters and demonstrate the shortcomings of some of the existing results. Furthermore, using nonlinear analyses we attempt to answer three fundamental questions: when does an instability occur, what is the mechanism of the instability, and what happens after the instability?
Subsequently, we develop nonlinear controllers to stabilize parallel dc-dc and parallel multi-phase converters. The proposed controllers for parallel dc-dc converters combine the concepts of multiple-sliding-surface and integral-variable-structure control. They are easy to design, robust, and have good transient and steady-state performances. Furthermore, they achieve a constant switching frequency within the boundary layer and hence can be operated in interleaving or synchronicity modes. The controllers developed for parallel multi-phase converters retain many of the above features. In addition, they do not require any communication between the modules; as such, they have high redundancy. One of these control schemes combines space-vector modulation and variable-structure control. It achieves constant switching frequency within the boundary layer and a good compromise between the transient and steady-state performances.Ph. D.
13
Prasantanakorn, Chanwit. „Current Sharing Method for DC-DC Transformers“. Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/31112.
Der volle Inhalt der QuelleAnnotation:
An ever present trend in the power conversion industry is to get higher performance at a lower cost. In a computer server system, the front-end converter, supplying the load subsystems, is typically a multiple output power supply. The power supply unit is custom designed and its output voltages are fully regulated, so it is not very efficient or cost effective. Most of the load systems in this application are supplied by point-of-load converters (POLs). By leaving the output voltage regulation aspect to POLs, the front-end converter does not need to be a fully regulated, multiple output converter. It can be replaced by a dc-dc transformer (DCX), which is a semi-regulated or unregulated, single output dc-dc converter. A DCX can be made using a modular design to simplify expansion of the system capacity. To realize this concept, the DCX block must have a current sharing feature.
The current sharing method for a resonant DCX is discussed in this work. To simplify the system architecture, the current sharing method is based on the droop method, which requires no communication between paralleled units. With this method, the current sharing error is inversely proportional to the droop voltage. In traditional DCX implementations, the droop voltage depends on the resistive voltage drops in the power stage, which is not sufficient to achieve the desired current sharing error. The resonant converter has the inherent characteristic that its conversion gain depends on the load current, so the virtual droop resistance can realized by the resonant tank and the droop voltage can be obtained without incurring conduction loss. An LLC resonant converter is investigated for its droop characteristic. The study shows the required droop voltage is achievable at very high switching frequency. To lower the switching frequency, a notch filter is introduced into the LLC resonant tank to increase the sensitivity of the conversion gain versus the operating frequency. The design of the multi-element resonant tank is discussed. Depending soly on the resonant tank, the droop characteristic is largely varied with the component tolerance in the resonant tank. The current sharing error becomes unacceptable. The active droop control is imposed to make the output regulation characteristic insensitive to the component tolerance. The proposed resonant DCX has simpler circuit structure than the fully regulated resonant converter. Finally simulation and experimental results are presented to verify this concept.Master of Science
14
Boora, Arash Abbasalizadeh. „Flexible high-power multi DC-DC converters for train systems“. Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/33208/1/Arash_Boora_Thesis.pdf.
Der volle Inhalt der QuelleAnnotation:
This thesis reports on the investigations, simulations and analyses of novel power electronics topologies and control strategies. The research is financed by an Australian Research Council (ARC) Linkage (07-09) grant. Therefore, in addition to developing original research and contributing to the available knowledge of power electronics, it also contributes to the design of a DC-DC converter for specific application to the auxiliary power supply in electric trains. Specifically, in this regard, it contributes to the design of a 7.5 kW DC-DC converter for the industrial partner (Schaffler and Associates Ltd) who supported this project. As the thesis is formatted as a ‘thesis by publication’, the contents are organized around published papers. The research has resulted in eleven papers, including seven peer reviewed and published conference papers, one published journal paper, two journal papers accepted for publication and one submitted journal paper (provisionally accepted subject to few changes). In this research, several novel DC-DC converter topologies are introduced, analysed, and tested. The similarity of all of the topologies devised lies in their ‘current circulating’ switching state, which allows them to store some energy in the inductor, as extra inductor current. The stored energy may be applied to enhance the performance of the converter in the occurrence of load current or input voltage disturbances. In addition, when there is an alternating load current, the ability to store energy allows the converter to perform satisfactorily despite frequently and highly varying load current. In this research, the capability of current storage has been utilised to design topologies for specific applications, and the enhancement of the performance of the considered applications has been illustrated. The simplest DC-DC converter topology, which has a ‘current circulating’ switching state, is the Positive Buck-Boost (PBB) converter (also known as the non-inverting Buck-Boost converter). Usually, the topology of the PBB converter is operating as a Buck or a Boost converter in applications with widely varying input voltage or output reference voltage. For example, in electric railways (the application of our industrial partner), the overhead line voltage alternates from 1000VDC to 500VDC and the required regulated voltage is 600VDC. In the course of this research, our industrial partner (Schaffler and Associates Ltd) industrialized a PBB converter–the ‘Mudo converter’–operating at 7.5 kW. Programming the onboard DSP and testing the PBB converter in experimental and nominal power and voltage was part of this research program. In the earlier stages of this research, the advantages and drawbacks of utilization of the ‘current circulating’ switching state in the positive Buck-Boost converter were investigated. In brief, the advantages were found to be robustness against input voltage and current load disturbances, and the drawback was extra conduction and switching loss. Although the robustness against disturbances is desirable for many applications, the price of energy loss must be minimized to attract attention to the utilization of the PBB converter. In further stages of this research, two novel control strategies for different applications were devised to minimise the extra energy loss while the advantages of the positive Buck-Boost converter were fully utilized. The first strategy is Smart Load Controller (SLC) for applications with pre-knowledge or predictability of input voltage and/or load current disturbances. A convenient example of these applications is electric/hybrid cars where a master controller commands all changes in loads and voltage sources. Therefore, the master controller has a pre-knowledge of the load and input voltage disturbances so it can apply the SLC strategy to utilize robustness of the PBB converter. Another strategy aiming to minimise energy loss and maximise the robustness in the face of disturbance is developed to cover applications with unexpected disturbances. This strategy is named Dynamic Hysteresis Band (DHB), and is used to manipulate the hysteresis band height after occurrence of disturbance to reduce dynamics of the output voltage. When no disturbance has occurred, the PBB converter works with minimum inductor current and minimum energy loss. New topologies based on the PBB converter have been introduced to address input voltage disturbances for different onboard applications. The research shows that the performance of applications of symmetrical/asymmetrical multi-level diode-clamped inverters, DC-networks, and linear-assisted RF amplifiers may be enhanced by the utilization of topologies based on the PBB converter. Multi-level diode-clamped inverters have the problem of DC-link voltage balancing when the power factor of their load closes to unity. This research has shown that this problem may be solved with a suitable multi-output DC-DC converter supplying DClink capacitors. Furthermore, the multi-level diode-clamped inverters supplied with asymmetrical DC-link voltages may improve the quality of load voltage and reduce the level of Electromagnetic Interference (EMI). Mathematical analyses and experiments on supplying symmetrical and asymmetrical multi-level inverters by specifically designed multi-output DC-DC converters have been reported in two journal papers. Another application in which the system performance can be improved by utilization of the ‘current circulating’ switching state is linear-assisted RF amplifiers in communicational receivers. The concept of ‘linear-assisted’ is to divide the signal into two frequency domains: low frequency, which should be amplified by a switching circuit; and the high frequency domain, which should be amplified by a linear amplifier. The objective is to minimize the overall power loss. This research suggests using the current storage capacity of a PBB based converter to increase its bandwidth, and to increase the domain of the switching converter. The PBB converter addresses the industrial demand for a DC-DC converter for the application of auxiliary power supply of a typical electric train. However, after testing the industrial prototype of the PBB converter, there were some voltage and current spikes because of switching. To attenuate this problem without significantly increasing the switching loss, the idea of Active Gate Signalling (AGS) is presented. AGS suggests a smart gate driver that selectively controls the switching process to reduce voltage/current spikes, without unacceptable reduction in the efficiency of switching.
15
Bills, David Marlin. „Soft Switching Multi-Resonant Forward Converter DC to DC Application for Communications Equipment“. Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3497.
Der volle Inhalt der QuelleAnnotation:
In the field of power electronics there is always a push to create smaller and more efficient power conversion systems. This push is driven by the industry that uses the power systems, and can be realized by new semiconductor devices or new techniques. This examination describes a novel technique for a small and highly efficient method of converting relatively high DC voltage to a very low voltage for use in the telecommunications industry. A modification to the standard Forward Resonant converter results in improvements in component stress, system efficiency, response time, and control circuitry. This examination describes background information needed to understand the concepts in DC to DC power systems, "soft-switching" topologies, and control methods for these systems. The examination introduces several topologies that are currently being used, and several types that have been previously analyzed, as a starting point for the detailed analysis of the proposed converter topology. A detailed analytical analysis is given of the proposed topology, including secondary effects, and component stresses. This analysis is compared to the results found from both Pspice simulation, and a working DC to DC converter. Finally, the topology is examined for potential improvements, and possible refinements to the model described.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
16
Perera, Lasantha Bernard. „Multi Level Reinjection ac/dc Converters for HVDC“. Thesis, University of Canterbury. Electrical and Computer Engineering, 2006. http://hdl.handle.net/10092/1085.
Der volle Inhalt der QuelleAnnotation:
A new concept, the multi level voltage/current reinjection ac/dc conversion, is described in this thesis. Novel voltage and current source converter configurations, based on voltage and current reinjection concepts are proposed. These converter configurations are thoroughly analyzed in their ac and dc system sides. The fundamentals of the reinjection concept is discussed briefly, which lead to the derivation of the ideal reinjection waveform for complete harmonic cancellation and approximations for practical implementation. The concept of multi level voltage reinjection VSC is demonstrated through two types of configurations, based on standard 12-pulse parallel and series connected VSC modified with reinjection bridges and transformers. Firing control strategies and steady state waveform analysis are presented and verified by EMTDC simulations. The multi level current reinjection CSC is also described using two configurations based on standard 12-pulse parallel and series connected CSC modified with associated reinjection circuitry. Firing control strategies and steady state waveform analysis are presented and verified by EMTDC simulations. Taking the advantage of zero current switching in the main bridge valves, achieved through multi level current reinjection, an advanced multi level current reinjection scheme, consisting thyristor main bridges and self-commutated reinjection circuitry is proposed. This hybrid scheme effectively incorporates self-commutated capability into a conventional thyristor converter. The ability of the main bridge valves to commutate without the assistance of a turn-off pulse or line commutating voltage under the zero current condition is explained and verified by EMTDC simulations. Finally, the applications of the MLCR-CSC are discussed in terms of a back to back HVDC link and a long distance HVDC transmission system. The power and control structures and closed loop control strategies are presented. Dynamic simulation is carried out on PSCAD/EMTDC to demonstrate the two systems ability to respond to varying active and reactive power operating conditions.
17
Wan, Hongmei. „High Efficiency DC-DC Converter for EV Battery Charger Using Hybrid Resonant and PWM Technique“. Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32343.
Der volle Inhalt der QuelleAnnotation:
The battery charger plays an important role in the development of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs).This thesis focuses on the DC-DC converter for high voltage battery charger and is divided into four chapters. The background related to EV battery charger is introduced, and the topologies of isolated DC-DC converter possibly applied in battery charge are sketched in Chapter 1. Since the EV battery charger is high voltage high power, the phase-shifted full bridge and LLC converters, which are popularly used in high power applications, are discussed in detail in Chapter 2. They are generally considered as high efficiency, high power density and high reliability, but their prominent features are also limited in certain range of operation. To make full use of the advantages and to avoid the limitation of the phase-shifted full bridge and LLC converters, a novel hybrid resonant and PWM converter combining resonant LLC half-bridge and phase shifted full-bridge topology is proposed and is described in Chapter 3. The converter achieves high efficiency and true soft switching for the entire operation range, which is very important for high voltage EV battery charger application. A 3.4 kW hardware prototype has been designed, implemented and tested to verify that the proposed hybrid converter truly avoids the disadvantages of LLC and phase-shifted full bridge converters while maintaining their advantages. In this proposed hybrid converter, the utilization efficiency of the auxiliary transformer is not that ideal. When the duty cycle is large, LLC converter charges one of the capacitors but the energy stored in the capacitor has no chance to be transferred to the output, resulting in the low utilization efficiency of the auxiliary transformer. To utilize the auxiliary transformer fully while keeping all the prominent features of the previous hybrid converter in Chapter 3, an improved hybrid resonant and PWM converter is proposed in Chapter 4. The idea has been verified with simulations. The last chapter is the conclusion which summaries the key features and findings of the two proposed hybrid converters.Master of Science
18
Merlin, Michael Marc Claude. „Hybrid multi-level HVDC converter and multi-terminal DC networks“. Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/39382.
Der volle Inhalt der QuelleAnnotation:
This thesis explains the working principles of an AC/DC converter topology intended for HVDC applications, called the Alternate Arm Converter (AAC). It consists of a hybrid between the modular multi-level converter (MMC) through the presence of H-bridge cells and the 2-level converter because of the director switches in each arm. Thanks to its cells, the AAC is able to generate a multi-level staircase AC voltage waveform which results a low distortion AC current while the director switches control which arms are conducting at any given time. By synchronising the conduction period of an arm with the zero-crossing points of the AC voltage waveform, the voltage rating of the stacks can be reduced, hence minimizing the number of cells. In case of a DC-side fault, an AAC with enough cells is able to keep control of the current in the phase reactor and even be operated to support the AC grid by providing reactive power similarly to a STATCOM. Since the AAC relies on pre-charged H-bridge cells, an effective energy management is required to control their level of charge. An ideal working point has been identified, called 'Sweet-Spot'. This operating point describes a set of conditions where the incoming and outgoing energy flows equate, in effect nullifying the average energy drift of the cells. Additional energy techniques based on current modulation have been developed in order to redistribute the energy inside the converter. The study of the AAC has provided an understanding of its working and device requirement and a hierarchical structure for its control system has been developed. Simulation results confirm these findings both on the operation of the AAC under normal and abnormal situations and on the effectiveness of the developed energy management system. Post-processing of the simulation data has also shown that the AAC is on par with the half-bridge MMC on power efficiency.
19
Cliffe, Robert J. „High power high frequency DC-DC converter topologies for use in off-line power supplies“. Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/7305.
Der volle Inhalt der QuelleAnnotation:
The development of a DC-DC converter for use in a proposed range of one to ten kilowatt off-line power supplies is presented. The converter makes good use of established design practices and recent technical advances. The thesis begins with a review of traditional design practices, which are used in the design of a 3kW, 48V output DC-DC converter, as a bench-mark for evaluation of recent technical advances. Advances evaluated include new converter circuits, control techniques, components, and magnetic component designs. Converter circuits using zero voltage switching (ZVS) transitions offer significant advantages for this application. Of the published converters which have ZVS transitions the phase shift controlled full bridge converter is the most suitable, and assessments of variations on this circuit are presented. During the course of the research it was realised that the ZVS range of one leg of the phase shift controlled full bridge converter could be extended by altering the switching pattern, and this new switching pattern is proposed. A detailed analysis of phase shift controlled full bridge converter operation uncovers a number of operational findings which give a better and more complete understanding of converter operation than hitherto published. Converter design equations and guidelines are presented and the effects of the new improvement are investigated by an approximate analysis. Computer simulations using PSPICE2 are carried out to predict converter performance. A prototype converter design, construction details and test results are given. The results obtained compare well to the predicted performance and confirm the advantages of the new switching pattern.
20
Mino, Kazuaki. „Novel hybrid unidirectional three-phase AC-DC converter systems /“. [S.l.] : [s.n.], 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18185.
Der volle Inhalt der Quelle
21
Filho, Herminio Miguel de Oliveira. „Soft switching bidirectional isolated three-phase DC-DC converter using dual phase-shift control with variable duty cycle“. Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16346.
Der volle Inhalt der QuelleAnnotation:
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorThis work presents the analysis, design example, simulations and experimental results on a soft-switching bidirectional isolated three-phase dc-dc converter using dual phase-shift control with variable duty cycle. The topology uses three single H-bridges in the primary side and a three-phase inverter in the secondary side. High-frequency isolation is ensured by using three single-phase transformers connected in open delta-wye configuration. The variation of both phase-shift (PS) angles between the H-bridge legs and/or primary and secondary sides allows controlling the power flow, while reduced reactive power flow is possible. The variable duty cycle is used to ensure a constant voltage bus and/or zero voltage switching (ZVS) operation. A detailed analysis is presented considering a model based on the fundamental components for the voltages and currents in the transformer and, aiming its validation, a second analysis from the operation stages of the converter has also been developed. Besides, the dynamic model of the converter, based on fundamental components and employing the gyrator theory has been developed. A design example with nominal values assumptions, stresses and specifications for components, discrete control system characterization and its FPGA programming are presented. Simulation and experimental results in steady state and closed-loop performance are presented and discussed to validate the proposed approach.
Este trabalho apresenta a anÃlise, exemplo de projeto, simulaÃÃes e resultados experimentais de um conversor CC-CC trifÃsico isolado bidirecional com comutaÃÃo suave, dual phase shift (DPS) e razÃo cÃclica variÃvel. A topologia utiliza trÃs pontes H monofÃsicas no lado primÃrio e um inversor trifÃsico no lado secundÃrio. A isolaÃÃo em alta frequÃncia à garantida utilizando-se trÃs transformadores monofÃsicos conectados em uma configuraÃÃo delta aberto/estrela. A variaÃÃo de ambos os Ãngulos de deslocamento de fase, entre os braÃos de uma ponte H e/ou entre os lados primÃrio e secundÃrio, permitem o controle do fluxo de potÃncia. Esta flexibilidade garante a obtenÃÃo de um baixo conteÃdo reativo na anÃlise de projeto da topologia. A razÃo cÃclica variÃvel à utilizada para assegurar um barramento constante e uma operaÃÃo dos interruptores com comutaÃÃo suave. Uma anÃlise matemÃtica da estrutura à apresentada considerando um modelo baseado em componentes fundamentais e, com o propÃsito de comprovar a validade deste modelo, uma segunda anÃlise a partir das etapas de operaÃÃo do conversor tambÃm foi desenvolvida. O modelo dinÃmico do conversor, baseado nas componentes fundamentais, tambÃm foi concebido com auxÃlio da teoria do gyrator. Um exemplo de projeto, com a obtenÃÃo de valores nominais, esforÃos e especificaÃÃes dos componentes, caracterizaÃÃo do sistema de controle discreto e sua programaÃÃo atravÃs de FPGA sÃo desenvolvidos. SimulaÃÃes e resultados experimentais do conversor operando em regime permanente e dinÃmico sÃo apresentados para validar o modelo proposto.
22
Wu, Kuiyuan. „Analysis and design of isolated bidirectional DC-DC converter with novel triple phase-shift control“. Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42815.
Der volle Inhalt der QuelleAnnotation:
The bidirectional DC-DC converter is widely used in automobiles, energy storage systems, uninterruptible power supplies and aviation power systems. At present, there are three main problems in this area. The first problem concerns stability of the bidirectional converter when parameters change; the second is maintaining high efficiency of the bidirectional converter over wide load range; the third concerns the sensitivity of the efficiency of the bidirectional converter to parameter changes. This thesis presents a new method to determine the stability of the bidirectional converter using the Lyapunov function method under arbitrary parameter changes. As another new contribution, the stability analysis with eigenvalue method is presented when only the input voltage changes. Although these two methods are used in this thesis to determine the stability of bidirectional dual full bridge DC-DC converter with triple phase-shift control, they can be used to determine the stability of other power converters composed of various power switches and controlled with different control methods. A novel triple phase-shift control method is developed in this thesis to make the bidirectional converter operate at high efficiency and make it robust to parameters changes and output power variations. Simulation results illustrate that the novel control method is better than several other commonly used control methods for the bidirectional converter when component parameters and output power change. The working theory of the bidirectional converter with novel triple phase-shift control method is comprehensively described in the thesis. As another new contribution, the maximum output power of the bidirectional converter is analyzed in detail in the thesis. Simulation studies of this project have provided satisfactory results. Conclusions are made on the presented work and possible future directions in continuing the work are indicated.
23
Urciuoli, Damian. „Switching Stage Design and Implementation for an Efficient Three-Phase 5kW PWM DC-DC Converter“. Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34378.
Der volle Inhalt der QuelleAnnotation:
With the development of fuel cell based power systems, the need for more advanced DC-DC power converters has become apparent. In such applications DC-DC converters provide an important link between low voltage fuel cell sources and inverter buses operating at significantly higher voltages. Advancements in converter efficiency, cost reduction, and size reduction are the most necessary. These challenges are formidable, even when considering the improvements made to conventional DC-DC topologies. However, it can be possible to achieve these criteria through the implementation of more advanced topologies.
A recently developed efficient three-phase DC-DC topology offers benefits over standard designs. Passive component sizes and output ripple voltage were reduced as a result of an effective boost in switching frequency. Converter output voltage was reached more easily due to an increased transformer voltage boost ratio in addition to the turns ratio. For cost reduction, the converter was designed and built with discrete components instead of more expensive integrated modules.
This thesis presents an overview of the three-phase converter, with a detailed focus on the design, implementation, and performance of the switching stage. The functionality of the three-phase topology is covered along with the selection of converter components. Simulation results are shown for both ideal and real converter models. Considerations for the switching device package with respect to circuit board and heat sinking configurations are discussed in support of the selection of an insulated metal substrate (IMS) circuit board. An effective circuit layout designed to minimize parasitic trace inductances as well as provide favorable component positioning is presented. Experimental converter test results are shown and the causes of undesired effects are identified. Switching stage modifications and their results are discussed along with the benefits of proposed future design enhancements.Master of Science
24
Thomas, Stephan [Verfasser]. „A Medium-Voltage Multi-Level DC/DC Converter with High Voltage Transformation Ratio / Stephan Thomas“. Aachen : Shaker, 2014. http://d-nb.info/1049383176/34.
Der volle Inhalt der Quelle
25
Saleemi, Furqan Mubashir. „Analysis and Design of Multiphase Multi-Interleave DC-DC Converter with Input-Output Bypass Capacitor“. DigitalCommons@CalPoly, 2008. https://digitalcommons.calpoly.edu/theses/24.
Der volle Inhalt der QuelleAnnotation:
The power requirements for the microprocessor have been increasing as per Moore's Law. According to International Technology Roadmap (ITRS), the Voltage Regulator Module (VRM) for the microprocessor will be 200 W(with 1V, 200A output) in 2010. With the VRMs topology of synchronous buck, serious technical challenges such as small duty cycle, high switching frequencies, and higher current demands, contribute to decreased power density and increased cost. This thesis proposes a Multiphase Multi-Interleave Buck topology to solve the technical challenges of powering future microprocessors. The critical design parameter values are selected using the theoretical design equations and calculations. The design is simulated in OrCAD Pspice to evaluate the performance criteria of the VRM. A prototype of four-phase Multiphase Multi-Interleave Buck Converter is constructed. The critical performance parameters of the prototype are tested and measured. The thesis concludes with the performance of the prototype as compared with the performance of the design simulation.
26
Meola, Marco. „Design and modeling of a digital controller for multi mode DC-DC convertes“. Doctoral thesis, Università degli studi di Trieste, 2010. http://hdl.handle.net/10077/3677.
Der volle Inhalt der QuelleAnnotation:
2008/2009Convertitori dc-dc in grado di fornire una elevata efficienza per un ampio intervallo di valori di carico trovano il loro impiego in tutte quelle applicazioni dove dispositivi alimentati a batteria vengono utilizzati. In particolare, l’ottimizzazione dell’efficienza di tali convertitori per basse correnti di carico `e uno degli argomenti pi`u stimolanti nella progettazione di convertitori dc-dc. Nei convertitori multi-modo tale efficienza viene massimizzata mediante l’utilizzo di strategie di controllo diverse in funzione della corrente di uscita. In quest’ambito, il controllo di convertitori a commutazione `e tradizionalmente ottenuto per via analogica tramite l’impiego di circuiti integrati dedicati. Tuttavia, mano a mano che i sistemi di potenza diventano sempre pi`u complessi e spesso costituiti a loro volta da sotto-sistemi fra loro interagenti, il classico concetto di controllo si `e gradualmente evoluto nella pi`u generale tematica del power management, richiedendo funzionalit`a difficilmente implementabili nei controllori analogici. L’elevata flessibilit`a offerta dai controllori digitali e la loro predisposizione ad implementare sofisticate strategie di controllo, insieme alla programmabilit`a dei parametri del controllore, fanno del controllo digitale una attraente alternativa per il miglioramento delle prestazioni dei convertirori dc-dc multi-modo. Tuttavia, il punto debole pi`u evidente di un controllore digitale risiede nelle prestazioni dinamiche a catena chiusa da esso ottenibili. I tempi impiegati per la conversione analogico-digitale della grandezza da controllare, i ritardi di calcolo cos`ı come i ritardi associati al campionamento pongono limiti severi alla massima banda di controllo ottenibile in un convertitore controllato digitalmente. Ulteriori limitazioni sono inoltre imposte dagli effetti di quantizzazione nella catena di controllo. Per le ragioni sopra esposte, la realizzazione di controllori digitali in grado di essere competitivi (in termini di prestazioni dinamiche) rispetto alle classiche soluzioni analogiche `e materia di 3 intensa attivit`a scientifica nonch´e interesse industriale. Inoltre, sebbene il controllo digitale appare capace di soddisfare le esigenze sopra menzionate, i convertitori dc-dc a controllo analogico dominano ancora il mercato. Infatti, il controllo digitale di convertitori dc-dc soffre della mancanza del solido know-how posseduto dai controllori analogici, risultando cos`ı meno accessibile. Questo lavoro di tesi si inquadra nel contesto cos`ı delineato. L’attivit`a principale svolta riguarda la progettazione e simulazione di controllori dc-dc a controllo digitale con l’obbiettivo di studiare l’ottimizzazione dell’efficienza per piccole correnti di carico. In questa tesi la struttura di un controllore digitale multi-modo per convertitori a basso costo e bassa consumo di potenza `e presentata. Criteri decisionali sulla scelta della strategia di controllo a seconda delle condizioni di carico sono proposti e testati su prototipo sperimentale di convertitore dc-dc dove il controllo digitale `e implementato in una FPGA. Inoltre, lo sviluppo di un modello a larghi segnali a tempo discreto dello stadio di potenza del convertitore, studiato appositamente per modellizzare il comportamento del convertitore nel passaggio da una strategia di controllo all’altra, costituisce un utile strumento per la progettazione di convertitori a commutazione sulla base dei criteri decisionali proposti, mettendo in luce le problematiche della progettazione di sistemi per il power management.
XXII Ciclo
1980
27
Oshaben, Edward J. „DC-DC Power Converter Design for Application in Welding Power Source for the Retail Market“. Cleveland State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=csu1296178360.
Der volle Inhalt der Quelle
28
Pepa, Elton. „Adaptive Control of a Step-Up Full-Bridge DC-DC Converter for Variable Low Input Voltage Applications“. Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9722.
Der volle Inhalt der QuelleAnnotation:
This thesis shows the implementation of a novel control scheme DC-DC converter. The converter is a phase-shifted full-bridge PWM converter that is designed to operate as a front stage of a power conversion system where the input is a variable low voltage high current source. The converter is designed to step-up the low voltage input to an acceptable level that can be inverted to a 120/240 VAC 60Hz voltage for residential power. A DSP based adaptive control model is developed, taking into account line variations introduced by the input source while providing very good load dynamics for the converter in both discontinuous and continuous conduction modes. The adaptive controller is implemented using two voltage sensors that read the input and the output voltages of the converter. The controller's bandwidth is comparable to current mode control, without the need for an expensive current sensor, yet providing the noise immunity seen in voltage mode controllers. The intended input source was a fuel cell but in its absence a DC supply is utilized instead. The system is simulated for both discontinuous and continuous conduction modes and implemented and demonstrated for the continuous conduction mode. The test results are shown to match the simulation results very closely.Master of Science
29
Cheng, Sheng-Wen, und 鄭勝文. „Design and Implementation of a Multi-Phase Buck DC-DC Converter for Blade Servers“. Thesis, 2014. http://ndltd.ncl.edu.tw/handle/46655847937705213867.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺灣科技大學
電機工程系
102
In this thesis, a digitally-controlled voltage regulation module (VRM) which is fully compliant with Intel® VR12.5 specifications is implemented. In the presented system, a four-phase buck converter topology is adopted. An IR3581 dual-loop digital multi-phase buck controller is utilized as the digital controller, and IR3578 integrated synchronous buck driver IC is used to implement the power stage. Advantages of using a digital controller and integrated driver chip include fewer peripheral components and high design flexibility. Main features of IR3581 controller include digital compensator design, dynamic phase control (DPC) and adaptive transient algorithm (ATA). DPC automatically adds/drops phases based upon load current, which will improve the converter efficiency at light load condition. ATA based on non-linear digital PWM algorithms can minimize bulk output capacitors. Experimental results validate that the implemented system can meet the Intel® VR12.5 specifications, and the measured efficiency is higher than 94%.
30
Kang, Zhe-Wei, und 康哲維. „Study of a Multi-Phase Isolated DC/DC Converter for PEM Fuel Cell Stacks“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33731010025977904061.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺灣科技大學
電子工程系
98
Recently, clean energy resources, such as wind turbines, photovoltaic systems or fuel cells, have been exploited for developing renewable electric power generation systems. Among them, the rapid advances in fuel cell technology have enabled the significant developments in fuel cell power system. The fuel cells feature numerous advantages, such as high energy density, high current output ability, and high-efficiency operation. However, the fuel cell stacks present a low voltage output and a wide range of voltage variations under different load, temperature, humidity and electrochemical reaction conditions. A step-up power converter is therefore applied to obtain a high output voltage from the fuel cell system. A high-performance isolated multi-phase power converter for fuel cell power systems is studied and implemented. A digital controller is also designed to perform the interleaved operation of the paralleled multi-phase power modules. Finally, a 10-kW converter prototype is implemented and tested to verify the feasibility of the studied topology and control strategy.
31
Hung, Ming-Fu, und 洪銘福. „The Design and Application of the Three Phase AC-DC Converter Simplified to the Single Phase DC-DC Converter“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/cc5m7n.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺北科技大學
電機工程系研究所
97
Three-phase AC-DC converters are gradually and widely being used in industry mainly for the improvement of the quality of the input current and adjust the magnitude of output voltage. By using the switch, the voltage and current on the input side are adjusted to be in-phase. As more and more types of three-phase AC-DC circuit topologies have been invented, usually the three-phase AC-DC converters are analyzed through the D-Q transformation. In the D-Q domain, the State Space equation are mutually coupled, thus the design of the control system is still difficult and complicated. In references, usually only the small signal equivalent model, the transfer function and the controller design of single-phase DC-DC converters are described in detail. However, the study of those for the three-phase AC-DC converter has not been dealt with in depth. The object of this paper is to propose a simplified method for modeling the three-phase AC-DC converters in order to extensively apply the knowledge of single-phase DC-DC converters to the simplified modeling of three-phase AC-DC converters. The paper shows that after the simplification is completed, the principles which work for single-phase DC-DC converter are able to be applied to the simplification model of three-phase AC-DC converter as well. The paper would be a helpful reference to people who need to design and analyze the control systems of the three-phase AC-DC converter.
32
Tsai, Chia-Hao, und 蔡家豪. „Study of a 10kW Multi-Phase Digital-Controlled DC/DC Converter for Fuel Cell Applications“. Thesis, 2011. http://ndltd.ncl.edu.tw/handle/c2h6a2.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺灣科技大學
電子工程系
99
Recently, clean energy resources such as solar cell, wind turbine or fuel cell have been exploited for developing renewable electric power generation systems. The fuel cell is considered as the most clean energy technology. Its major advantages include low noise, low pollution, high efficiency, and easy replacement. However, the fuel cell stacks present low voltage output and wide range of voltage variation. In order to provide load a constant source, a step-up DC-DC converter must be inserted between the fuel cell stack and the load. In this thesis, the adopted circuit topology is the current-fed full-bridge boost converter with secondary voltage-doubler. A digital controller is also designed to coordinate the interleaved parallel operation among the multi-phase power modules. An auxiliary power is used to provide digital signal processor (5V/3A), drive circuit (15V/2A) and the feedback circuit (15V/0.67A). An improved high-performance isolated multi-phase power converter is studied and implemented for fuel cell power systems. Finally, a 10kW DC-DC boost converter is implemented, Experimental results are shown to verify the feasibility of the developed system. A high conversion efficiency over 90% can be achieved.
33
Feng, Yi-Hsin, und 馮毅昕. „Three-Phase Multi-Level Y-Y Connection Bi-Directional Series-Series Resonant DC-DC Converter“. Thesis, 2018. http://ndltd.ncl.edu.tw/handle/9ucj8t.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺灣科技大學
電子工程系
106
This thesis presents Three-Phase Multi-Level Y-Y connection Bi-Directional Series-Series Resonant DC-DC Converter. The voltage stress of the power switch is equal to half of the input voltage. Therefore, it is suitable for high input-voltage applications, and is easy to choose the power switch device, it also has the benefit of reducing output voltage and current ripple. This article will introduce the principle of Three-Phase Multi-Level Y-Y connection Bi-Directional Series-Series Resonant DC-DC Converter. On secondary side, synchronous rectification is added to reduce the conduction loss, and a digital signal processor DSP is used to control the switching signal to achieve multi-stage voltage equalization control. Finally, a laboratory prototype of Three-Phase Multi-Level Y-Y connection Bi-Directional Series-Series Resonant DC-DC Converter was designed and tested for high-voltage applications. The circuit specifications are 7 kW rated power, 800 V input voltage, and 8.75 A output current. The measured efficiency can be up to 96% under different load conditions.
34
Chang, Jie_Kuan, und 張介寬. „Implementation of Phase-Shift Full-Bridge DC/DC Power Converter“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/26139847877372803567.
Der volle Inhalt der QuelleAnnotation:
碩士國立高雄應用科技大學
電機工程系
98
In this paper, a non-isolated gate driver circuit is developed for driving the power electronic switches of the diode-clamped three-level power converter, and a phase-shift full-bridge DC/DC power converter is also developed. The developed non-isolated gate driver circuit is composed of the bootstrap-type charge pump circuit and discrete electronic devices. A voltage source using bootstrap charge pump circuit is used to generate four isolated power supplies and four pulse-width modulation signals using a constant current couple mode are used for shifting the signal level. Four different levels of independent power supplies and PWM signals are used to control power electronic switches. A prototype developed by discrete devices is built for verifying the performance of the developed non-isolated gate driver circuit. The experimental results show the feasibility of the developed non-isolated gate driver circuit. This paper will developed a phase-shifted full-bridge DC/DC power converter. The power switch can be controlled by the phase shift control method and using the leakage inductance of transformer to achieve zero voltage switch characteristics to reduce the switching losses. Therefore, the efficiency of DC/DC power converter can be improved. This will be the development phase-shifted full-bridge DC/DC power converter prototype hardware. Experimental results verify the phase-shifted full-bridge DC / DC power converter has the desired function.
35
„Digital Controlled Multi-phase Buck Converter with Accurate Voltage and Current Control“. Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.46206.
Der volle Inhalt der QuelleAnnotation:
abstract: A 4-phase, quasi-current-mode hysteretic buck converter with digital frequency synchronization, online comparator offset-calibration and digital current sharing control is presented. The switching frequency of the hysteretic converter is digitally synchronized to the input clock reference with less than ±1.5% error in the switching frequency range of 3-9.5MHz. The online offset calibration cancels the input-referred offset of the hysteretic comparator and enables ±1.1% voltage regulation accuracy. Maximum current-sharing error of ±3.6% is achieved by a duty-cycle-calibrated delay line based PWM generator, without affecting the phase synchronization timing sequence. In light load conditions, individual converter phases can be disabled, and the final stage power converter output stage is segmented for high efficiency. The DC-DC converter achieves 93% peak efficiency for Vi = 2V and Vo = 1.6V.Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2017
36
Chou, Hung-Ming. „Multi-port DC-DC Power Converter for Renewable Energy Application“. 2009. http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-837.
Der volle Inhalt der QuelleAnnotation:
In recent years, there has been lots of emphasis put on the development of renewable
energy. While considerable improvement on renewable energy has been made,
there are some inherent limitations for these renewable energies. For example, for
solar and wind power, there is an intermittent nature. For the fuel cell, the dynamics
of electro-chemical reaction is quite slow compared to the electric load. This will
not be acceptable for modern electric application, which requires constant voltage of
constant frequency.
This work proposed and evaluated a new power circuit that can deal with the
problem of the intermittent nature and slow response of the renewable energy.
The proposed circuit integrates different renewable energy sources as well as
energy storage. By integrating renewable energy sources with statistical tendency to
compensate each other, the effect of the intermittent nature can be greatly reduced.
This integration will increase the reliability and utilization of the overall system.
Moreover, the integration of energy storage solves the problem of the slow response
of renewable energy. It can provide the extra energy required by load or absorb the
excessive energy provided by the energy sources, greatly improving the dynamics of
overall system.
To better understand the proposed circuit, "Dual Active Bridge" and "Triple
Active Bridge" were reviewed first. The operation principles and the modeling were presented. Analysis and design of the overall system were discussed. Controller
design and stability issues were investigated. Furthermore, the function of the central
controller was explained. In the end, different simulations were made and discussed.
Results from the simulations showed that the proposed multi-port DC-DC power
converter had satisfactory performance under different scenarios encountered in practical
renewable energy application. The proposed circuit is an effective solution to the
problem due to the intermittent nature and slow response of the renewable energy.
37
Lusney, John Travis. „Novel Digital Controller for Multi Full-Bridge DC/DC Converter“. Thesis, 2007. http://hdl.handle.net/1974/716.
Der volle Inhalt der QuelleAnnotation:
Distributed generation that utilizes 5-10kW Solid Oxide Fuel Cells requires power electronics to optimize the overall system efficiency while reducing the cost. The Adaptive Energy Zero-Voltage-Switching Phase-Shift-Modulated Full-Bridge (AE-ZVS-PSM-FB) topology meets these criteria under all loading conditions, but suffers from complexity associated with an analog control implementation. This thesis presents a novel Look-Up-Table (LUT) based digital controller required for such converter. The applied design approach also reduces the design time and controller requirements, which in turn decreases the overall system cost.
Steady-state analysis for the AE-ZVS-PSM-FB converter is performed using a piece-wise equivalent circuit model. This analysis is used to verify the LUT concept that forms the basis for the proposed LUT-based digital controller. The proposed LUT-based digital control algorithm is developed and verified using Field Programmable Gate Array (FPGA) Logic platform. Design procedures and operational function under steady state and step change conditions are presented.
Simulation results demonstrate the LUT concept in the AE-ZVS-PSM-FB converter, and the simplicity of the proposed LUT-based digital controller in producing the expected switching sequence. Simulation results were also produced showing successful dynamic response of LUT-based digital controller interconnected with the converter under different operating conditions. A Xilinx FPGA demonstration board was used to generate experimental switching sequence results to demonstrate the simplicity of the proposed controller.Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-09-25 10:26:39.909
38
Yang, Zhen-Yu, und 楊鎮宇. „Multi-objective Optimization for RCD Snubber of DC-DC Converter“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/83877765414325253465.
Der volle Inhalt der QuelleAnnotation:
碩士國立高雄第一科技大學
系統資訊與控制研究所
100
In this paper, we propose that Multi-objective algorithm and the Taguchi method be employed in the optimal design of a DC-DC converter with an RCD snubber. The RCD snubber is usually used in flyback converter to limit the voltage spikes which are caused by leakage inductance of the transformer. The design considerations of RCD snubber are commonly two objectives: (1) minimize power loss in the snubber ; (2) minimize the voltage spikes across the transistor. But the RCD design consideration for voltage spikes suppression is usually in contradiction with power loss. So we implement the circuit by using optimal trade-off parameters, which results from comparison of pareto solution set of Multi-objective Differential Evolution (MODE), Non-Dominated sort genetic algorithm-II (NSGA-II) and Multi-objective particle swarm optimization (MOPSO) methods. Finally, the comparison of the spike voltage and power loss showed the advantages of the optimal circuit design over a non-optimal design .
39
Chen, Yan-Ru, und 陳彥儒. „A Voltage-mode PWM Dual-phase DC-DC Boost Converter with Phase Shedding“. Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8tucf8.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺灣海洋大學
電機工程學系
107
In recent years, the dc-dc converter output current needs to be higher in the power management systems. The traditional dc-dc converters uses a single power stage. However, if a single power stage is used to output a higher output current may cause the inductor to withstand a lager current that makes input capacitor current ripple and inductor volume larger. In order to solve this problem, the power stages in parallel are adopted instead that spreads the input current evenly to each of power stage to reduce current on the inductor thereby reducing the inductor volume, input capacitor current ripple cancellation, and improving system conversion efficiency. The type of dc-dc converter is known as multi-phase dc-dc converter. Although the use of multi-phase dc-dc converters can improve system conversion efficiency at heavy loads, it can be inefficient at light loads due to switching losses of multiple sets of power transistors (Power MOS) and circuit power consumption. Therefore, usually the multi-phase dc-dc converter switches the number of phase according to the output current to achieve the best efficiency. This technique is called phase shedding, and as the number of phase becomes smaller, the efficiency is improved at light load. In this thesis, we achieve a voltage-mode duel-phase PWM boost dc-dc converter with phase shedding. Because the traditional multi-phase converters use external signals to control the number of phase, this thesis proposes a novel phase shedding detection circuit that senses inductor current to determine the load current and obtains the phase switching signal to switch the number of phase. This chip has been implemented using TSMC 0.35um Mixed-Signal 2P4M Polycide 5V process. The input voltage ranges from 3.6 V to 4.2V, output voltage is 5V, load current ranges from 10mA to 1500mA, switching frequency is 1MHz for each of phase, peak efficiency is 95.7%, maximum output ripple voltage is 0.6%, and chip area is 2.031×1.745mm2.
40
Yancey, Billy Ferrall. „Performance Evaluation of a Multi-Port DC-DC Current Source Converter for High Power Applications“. Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7789.
Der volle Inhalt der QuelleAnnotation:
With the ever-growing developments of sustainable energy sources such as fuel
cells, photovoltaics, and other distributed generation, the need for a reliable power
conversion system that interfaces these sources is in great demand. In order to provide
the highest degree of flexibility in a truly distributed network, it is desired to not only
interface multiple sources, but to also interface multiple loads. Modern multi-port
converters use high frequency transformers to deliver the different power levels, which
add to the size and complexity of the system. The different topological variations of the
proposed multi-port dc-dc converter have the potential to solve these problems.
This thesis proposes a unique dc-dc current source converter for multi-port power
conversion. The presented work will explain the proposed multi-port dc-dc converter's
operating characteristics, control algorithms, design and a proof of application. The
converter will be evaluated to determine its functionality and applicability. Also, it will
be shown that our converter has advantages over modern multi-port converters in its ease
of scalability from kW to MW, low cost, high power density and adaption to countless combinations of multiple sources. Finally we will present modeling and simulation of
the proposed converter using the PSIM software.
This research will show that this new converter topology is unstable without
feedback control. If the operating point is moved, one of the source ports of the multiport
converter becomes unstable and dies off supplying very little or no power to the
load while the remaining source port supplies all of the power the load demands. In
order to prevent this and add stability to the converter a simple yet unique control
method was implemented. This control method allowed for the load power demanded to
be shared between the two sources as well as regulate the load voltage about its desired
value.
41
Deepak, G. „Integrated Magnetics Based DC-DC Converter Topologies For A DC Micro-Grid“. Thesis, 2012. https://etd.iisc.ac.in/handle/2005/2310.
Der volle Inhalt der QuelleAnnotation:
In the present day, owing to the increasing number of electronic loads such as computer power supplies, Compact fluorescent lamps (CFL) and the increasing number of sources such as solar photovoltaics, fuel cells (DC sources), DC Micro-grids provide a more efficient solution compared to the AC counterpart in terms of the number of stages involved in conversion. Also, the ability to be readily buffered to storage elements is an advantage in a DC system. Apart from this, there are no issues of frequency stability, reactive power transfer and ac power losses.
A DC micro-grid is effectively a multi-port dc-dc converter. The ports refer to the various sources and loads that are part of the micro-grid. Sources could be unidirectional (as in the case of PV, load) or bidirectional (as in the case of batteries). Interfacing a variety of ports and controlling power flow between these ports presents an interesting challenge.
Commonly used topologies interface the various ports at the DC bus capacitor thereby making the DC bus capacitor bulky. Apart from this, the DC bus coupled topologies route power from one port to another via the central capacitor. This increases the number of stages in transferring power from one port to another. An alternative topology is to use the active bridge type converters where dynamic power flow equations are required to control inter-port power flow. But, as the number of stages increase, the computations get tedious.In this thesis, a novel topology is proposed that uses a UU type transformer core to interface all the power ports. This alleviates the problems faced in the DC bus coupled topologies. A PWM scheme to control simultaneous power flow from each of the ports is also proposed in this thesis. The PWM scheme enables the usage of simple constant frequency average current mode control to dynamically control power sharing ratio between the various ports delivering to loads. By means of the proposed PWM scheme and the control scheme, the drawbacks of the active bridge topologies are alleviated. Using the proposed topology and the PWM scheme, a prototype micro-grid system is developed for a system comprising of the utility grid, batteries, solar PVs and resistive loads. Yet another aspect of the thesis explores the concept of connecting multiple micro-grids in order to create a 'local power network'. A potential application for this could be in interconnecting residential buildings and routing power from one house to another in order to balance demand and supply among these houses. This is against the growing trend of using the utility grid to also sink power and subsequently route it to other houses connected to the grid. Unfortunately not all areas have access to the utility grid. Additionally, turning the grid bidirectional requires that a number of standards be met and policies be created. But, the standard for using a local network that only involves a unidirectional grid is fixed by the community that owns such a network. In a crude sense, this scenario can be compared to the existence of a local area network to transfer information among users of the network. In this thesis, a prototype local power network interconnecting two micro-grids has been implemented.
42
Deepak, G. „Integrated Magnetics Based DC-DC Converter Topologies For A DC Micro-Grid“. Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2310.
Der volle Inhalt der QuelleAnnotation:
In the present day, owing to the increasing number of electronic loads such as computer power supplies, Compact fluorescent lamps (CFL) and the increasing number of sources such as solar photovoltaics, fuel cells (DC sources), DC Micro-grids provide a more efficient solution compared to the AC counterpart in terms of the number of stages involved in conversion. Also, the ability to be readily buffered to storage elements is an advantage in a DC system. Apart from this, there are no issues of frequency stability, reactive power transfer and ac power losses.
A DC micro-grid is effectively a multi-port dc-dc converter. The ports refer to the various sources and loads that are part of the micro-grid. Sources could be unidirectional (as in the case of PV, load) or bidirectional (as in the case of batteries). Interfacing a variety of ports and controlling power flow between these ports presents an interesting challenge.
Commonly used topologies interface the various ports at the DC bus capacitor thereby making the DC bus capacitor bulky. Apart from this, the DC bus coupled topologies route power from one port to another via the central capacitor. This increases the number of stages in transferring power from one port to another. An alternative topology is to use the active bridge type converters where dynamic power flow equations are required to control inter-port power flow. But, as the number of stages increase, the computations get tedious.In this thesis, a novel topology is proposed that uses a UU type transformer core to interface all the power ports. This alleviates the problems faced in the DC bus coupled topologies. A PWM scheme to control simultaneous power flow from each of the ports is also proposed in this thesis. The PWM scheme enables the usage of simple constant frequency average current mode control to dynamically control power sharing ratio between the various ports delivering to loads. By means of the proposed PWM scheme and the control scheme, the drawbacks of the active bridge topologies are alleviated. Using the proposed topology and the PWM scheme, a prototype micro-grid system is developed for a system comprising of the utility grid, batteries, solar PVs and resistive loads. Yet another aspect of the thesis explores the concept of connecting multiple micro-grids in order to create a 'local power network'. A potential application for this could be in interconnecting residential buildings and routing power from one house to another in order to balance demand and supply among these houses. This is against the growing trend of using the utility grid to also sink power and subsequently route it to other houses connected to the grid. Unfortunately not all areas have access to the utility grid. Additionally, turning the grid bidirectional requires that a number of standards be met and policies be created. But, the standard for using a local network that only involves a unidirectional grid is fixed by the community that owns such a network. In a crude sense, this scenario can be compared to the existence of a local area network to transfer information among users of the network. In this thesis, a prototype local power network interconnecting two micro-grids has been implemented.
43
Kuo, Chung-wei, und 郭忠韋. „DESIGN AND IMPLEMENTATION OF A 16 PHASE DC/DC BUCK CONVERTER“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/45639020549716818024.
Der volle Inhalt der QuelleAnnotation:
碩士大同大學
電機工程學系(所)
98
ABSTRACT As the power consumption of microprocessors increase, a multi-phase voltage regulator is required to meet the power hunger and high efficiency requirements. In this thesis, in order to design and implementation of a 16 phase DC/DC buck converter, phase extender is applied on the power module of CPU on the motherboard. In general, the higher the phase number count, the more PWM outputs are required for the PWM controller. Consequently, developing a multi-phase PWM controller becomes very challenging and requires a high pin count package, resulting in high cost and complex layout design. In this thesis, the IC of the phase extender is applied, and which can extend a PWM signal to two interleaved PWM signals. As a result, the purpose of extending 8 phases to 16 phases is achieved, and that can overcome the above mentioned problems. Moreover, the efficiency simulation of 16 phases power consumption is analyzed in this thesis, and the experimental results are provided. In order to reduce the phase numbers in the low loading, enhance the phase numbers in the high loading, lower power consumption and increase the efficiency, the phase shedding is used according to the loading.
44
Lee, Kuo-Pao, und 李國葆. „Four-Phase Digital Pulse Width Modulation for Switching DC-DC Converter“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/04370010389678698552.
Der volle Inhalt der QuelleAnnotation:
碩士國立交通大學
電機學院碩士在職專班電機與控制組
97
The purpose of the thesis is to implement a fully digital pulse width modulation controlled DC to DC converter. This thesis is also aimed at building a mathematical effective module equal, circuit characterization and implementation to the fully digital pulse width modulation controlled DC to DC converter. The thesis uses a ready ADC device to sample the input voltage and output an Error. The Error sends to a pre-calculated lookup-table PID controller and output a pulse width modulation result. After the result processed by a four-phase buck converter, we can get the voltage converting result of the thesis. Here we use Verilog HDL and Xilinx ISE develop environment under ULINX FPGA board to verify the design and performance in the thesis.
45
Su, Chien-Chung, und 蘇建中. „Design of a Dual-phase Voltage-mode DC-DC Buck Converter“. Thesis, 2019. http://ndltd.ncl.edu.tw/handle/264jbg.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺灣海洋大學
電機工程學系
107
In recent years, technology has developed rapidly, and electronic products have become thinner and can use many functions at the same time. Lithium batteries need to provide many voltages to different system modules at the same time, and the usage time will be shortened as the power consumption becomes larger. An effective power management system is an important thing in a limited volume and battery capacity. A good power management system can extend the life of the product and reduce the frequency of battery charging. In view of the above mentioned problems, this thesis proposes a dual-phase voltage mode buck converter. The dual-phase converter is connected in parallel with two sets of power transistors. Compared with single phase, it has the advantages of low ripple voltage, large load current, and improving the efficiency of heavy loads. The phase control circuit uses one phase delay circuit to generate another set of switching signals. Since the converter has only one control circuit in dual-phase design, the number of control circuits can be reduced, thus the area of the entire chip can be decreased. The overall design is implemented with the TSMC 0.35um mixed signal 2P4M CMOS 5V process provided by the Taiwan Semiconductor Research Center (TSRI). The converter uses the voltage mode. The input voltage range is 3.3V~4.2V, the output voltage is 1.8V, the operating frequency is 1MHz per phase, the load range is 50mA~1000mA, the output ripple voltage is below 10mV, and the overall maximum efficiency is 92.17%.
46
Hsu, Lan-Ting, und 許嵐婷. „Modeling and Control of a Multi-Phase Step-Up DC/DC Converter with Low Switch Voltage Stress“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/33656679231194366909.
Der volle Inhalt der QuelleAnnotation:
碩士國立清華大學
電機工程學系
96
In recent years, with global energy shortage and strong environmental movements, many countries are encouraging and promoting the development of distributed energy sources such as fuel cells and renewable energies. As important roles in new energy, however, the output voltage of the solar cells and the fuel cells is rather low. Hence, a high step-up dc/dc converter is normally required as an interface to increase voltage for back-end applications. Therefore, emphasis of this thesis is placed on developing a high efficiency and high step-up dc/dc converter for these two new energy systems. Basically, the main contributions of this thesis can be summarized as follows. First, a new high efficiency and high step-up dc/dc converter is proposed. It can effectively reduce the voltage stress of active switches and the output voltage ripple of the converter. Moreover, it is able to maintain rather high efficiency in wide load range. Second, the mathematical model of the proposed converter is derived. According to the model, a close-loop controller is designed to achieve better stability and transient response of the converter. Finally, a 200V/100W laboratory prototype is constructed and corresponding simulations as well as experimental results are provided to verify the feasibility of the proposed converter. It is seen that the resulting efficiency curve can be maintained rather flat and above 93% for a load varied from 40W to 100W. Furthermore, the voltage stress of active switches and the output voltage ripple are 25% and 16.7%, respectively, lower than that of the voltage doubler proposed in 2007.
47
Dharmarajan, Vimala. „Three-level soft-switched DC-to-DC converter and single-phase, single-stage, three-level AC-to-DC converter“. Thesis, 2006. http://hdl.handle.net/1828/2335.
Der volle Inhalt der QuelleAnnotation:
This thesis proposes a three-level DC-to-DC converter with capacitive output filter and its extension to single-phase, single-stage, three-level AC-to-DC converter with capacitive output filter. The AC-to-DC converter integrates a three-level boost converter operating in discontinuous conduction mode (DCM) and a three-level half-bridge DC-to-DC converter with capacitive output filter.
The steady-state operation of the DC-to-DC converter and AC-to-DC converter with capacitive output filter are studied with phase-shifted gating scheme. The three-level topology reduces the voltage rating of the switches to half of the input voltage. Soft-switching is achieved for switches at different load and input voltage conditions. Boost section of the AC-to-DC converter achieves automatic power factor correction (PFC). At reduced load and higher input voltage conditions, the line current Total Harmonic Distortion (THD) increases with phase-shifted gating scheme. The THD has been reduced by using a complementary PWM gating control in the AC-to-DC converter.
48
SHIH, BO-CHEN, und 施柏辰. „Asymmetric Multi-Level DC-DC Power Converter Based On Board Charger“. Thesis, 2016. http://ndltd.ncl.edu.tw/handle/83977r.
Der volle Inhalt der QuelleAnnotation:
碩士國立高雄應用科技大學
電機工程系博碩士班
104
This thesis investigates an asymmetric multi-level dc-dc power converter based on board charger. This charger consists of a rectifier , a boost dc-dc converter and an asymmetric multi-level dc-dc power converter. A digital signal processors(DSP) is used to control the on board charger. The boost dc-dc converter has the performance of power factor correction and stabilizing the output capacitor voltage. The proposed asymmetric multi-level dc-dc converter is superior to the conventional multi-level dc-dc power converter due to improvement of energy efficiency. Computer simulation and hardware of 3.2kW prototype are developed to verify performance of the proposed on board charger with a power factor corrector and an asymmetric multi-level dc-dc power converter. Both simulation and experimental results show that the performance of the proposed on board charger with a power factor corrector and an asymmetric multi-level dc-dc power converter has the expected results.
49
Tsai, Cheng-Han, und 蔡承翰. „Applying FPGA Control Without ADC to Multi-Output DC-DC Converter“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/qynnck.
Der volle Inhalt der QuelleAnnotation:
碩士國立臺北科技大學
電機工程系研究所
97
In this thesis, the forward converter with multiple outputs is used to realize a system with fully-digitalized control without any analog-to-digital converter (ADC) used. In such a circuit, each output voltage can regulate itself via feedback control. Aside from this, the output voltage with the largest output current takes not only voltage control but also interleaved control and current sharing control. If such a system takes fully-digital control, then the number of ADCs used is large and hence the corresponding cost is expensive. Therefore, the sampling of multiple output voltages and two-phase currents without any ADC is presented herein. For the system control to be considered, an additional nonlinear control strategy is presented and added to the existing proportional integral derivative (PID) controller, so as to enhance the load transient response. In this paper, the multiple-output forward converter has three output voltages of 12V, 5V and 3.3V, where the output voltage of 3.3V possessing has the largest output current takes interleaved control and current sharing control. Via mathematical derivation and simulated waveforms, the feasibility of the proposed structure topology and control strategy can be verified. Furthermoore, the field programmable gate array (FPGA) is used as a control kernel of the system, so as to demonstrate the effectiveness of the proposed structure topology and control strategy.
50
Ko, Po Jen, und 柯柏任. „Design and Implementation of High Power Bidirectional Dual-Phase DC-DC Converter“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/59186179649025776489.
Der volle Inhalt der QuelleAnnotation:
碩士長庚大學
電機工程學系
98
This thesis designs and implements a hard-switching high power bidirectional dual-phase dc-dc converter. The converter accomplishes high power density operation in boost mode and buck mode. The maximum operating efficiency and power losses allocation of circuit elements used in the converter are also explored. EMI in the converter is also considered and reduced by using turn-off snubber circuits. In order to obtain high conversion efficiency under high power operating situation, this thesis discuses the specifications selection of circuit elements used in the converter. A TMS320LF2407 DSP-based digital controller is designed and implemented for high precision switching control of the converter. Finally, a hardware prototype is implemented. Experimented results show that the conversion efficiency can reach above 96.2% in boost mode, and 94.8% in buck mode at full power output conditions, respectively.