Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 129 for “"MMC"”.
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MOSFET-based MMC for low-voltage DC distribution networks
… a high-performance modular multilevel converter (MMC) with parallel-connected MOSFETs is proposed in this thesis. It allows the converter to operate at relatively high voltage with low harmonic content, without the use of large AC filters. MMC also has low switching frequency, and facilitates the …
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Control and operation of MMC-HVDC system for connecting offshore wind farm
… 80-100 km, modular multi-level converter (MMC) based high voltage DC (HVDC) system emerges as a more suitable solution than HVAC due to its flexible control and transmission distance not affected by the cable charging current. For HVDC connected wind farms, the offshore wind farm AC …
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Characterization of new particulate MMC materials and bolted joints through applicable ASTM standards
Particulate reinforced metal matrix composites (PRMMC) comprise a new class of materials whose properties can be adjusted to suit a particular application. The main purpose of producing PRMMC is to achieve lightweight materials with added properties like high stiffness, high ultimate strength and …
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Estudio de la tolerancia a fallos de convertidores multipuerto basados en topologías MMC
El convertidor Modular Multinivel (MMC) se ha convertido en una de las topologías multinivel más atractivas para aplicaciones de media/alta tensión, en particular para los sistemas de transmisión HVDC (High Voltage Direct Current). Sus características destacables son: • Una elevada …
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Application of Modular Multilevel Converters (MMC) Using Phase-Shifted PWM and Selective Harmonic Elimination in Distribution Systems
… solution using the modular multilevel converter (MMC) topology to design the MPS system. The market-available power semiconductor devices are analyzed and suitable devices are selected to design the system. The phase-shifted pulse width modulation (PS-PWM) and selective harmonic elimination (SHE) …
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Analysis and design of the modular multilevel converter for secure systems
… and design of modular multilevel converters (MMCs) for stable and reliable operation. The internal dynamics and control schemes of the conventional MMC is analysed with consideration of passive component tolerances. Detail qualitative and quantitative analysis of MMC internal dynamics with …
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Effect of Mitomycin C with different application method on rabbit corneal wound healing process after Excimer laser photortherapeutic keratectomy
… shape or discoid shape) soaked 0.02% Mitomycin C(MMC) for 2 minutes. Corneal haziness was described with slit lamp biomicroscope at postoperative 4, 12 & 24weeks. Histologic findings of keratocyte proliferation were observed at postoperative 4, 12 & 24 weeks after enucleation. At 4 weeks, …
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Perceptions regarding the Michigan merit curriculum reform policy and its impact on CTE and dual enrollment in a southeastern Michigan high school
… reform effort. The Michigan Merit Curriculum (MMC), mandated in 2006, contained a new set of statewide graduation requirements. This qualitative case study used focus group interviews to examine the perceptions of students, teachers, parents, and key administrators in a southeastern Michigan …
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Modular multilevel converters for solar photovoltaic - battery energy storage system integration
… structure, modular multilevel converters (MMC) are suitable for grid integration of PV and battery energy storage system (BESS). This thesis proposes a novel half-bridge submodule MMC (HBMMC) solution to connect distributed PV systems using distributed maximum power point tracking across …
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Mechanics of machining metal matrix composites: analytical modeling and finite element simulation
Metal matrix composites (MMCs) are commonly utilized materials in various industries, including applications in aerospace and automotive industries, due to their outstanding strength-to-weight ratio and wear resistance. In this thesis, a detailed understanding of MMC machining is accomplished …
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Wear of aluminium MMCs against automobile friction materials
… has been formulated for use against aluminium MMC brake rotors. Wear processes at the interfaces of the specific rotor - pad combinations have been characterised through the analysis of friction traces and the use of optical and electron microscopy. Models on the interdependence of friction and …
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High Voltage Direct Current Energy Transmission Using Modular Multilevel Converters
… transmission using modular multilevel converter (MMC) based terminals. It provides a brief comparison between different HVdc technologies, focusing on voltage source converters (HVdc-VSC) with the MMC-based terminal emerging as the topology of choice for ratings less than 1 GW. The controllers for …
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Optimal modulation and topology design of modular multilevel converter for grid integration of solar photovoltaic systems
Modular multilevel converter (MMC) stands out among converter topologies for medium/high-power applications. With salient features like modularity and scalability, MMC can meet the requirement of theoretically any voltage level with higher efficiency and superior harmonic performance, using …
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SECURE PLANT FERTILITY IN A CHANGING CLIMATE
The megaspore mother cell (MMC) development is a crucial step for plant reproduction. MMC specification is regulated by hormones, and many genes are involved. SPOROCYTELESS/NOZZLE (SPL/NZZ) is considered the master regulator of this process since its mutant cannot specify the MMC. It encodes a …
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Natural biosorbents for the removal of metals from aqueous solutions
… Mechanically and commercially milled carapace (MMC and CMC) were the most efficient, removing >95.0 % within 40 minutes from 100-1000 mg/L Cu(II) solutions. Extended studies showed MMC was also applicable for use in biosorption columns and effective for the removal of Cd(II), Hg(II), Pb(II), …
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Modeling and Control Strategy for Capacitor Minimization of Modular Multilevel Converters
The modular multi-level converter (MMC) is the most prominent interface converter used between the HVDC grid and the HVAC grid. One of the important design challenges in MMC is to reduce the capacitor size. In the current practice, a rather large capacitor bank is required to store line-frequency …
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Management of Myelomeningocele in Namibia
… on the surgical management of myelomeningocele (MMC) in Namibia. We had three objectives (1) Determine the occurrence of Spina Bifida (SB) in Namibia from 2017 to 2021, (2) Determine the management and outcomes of babies born with MMC/SB, (3) Determine the extent of multi-disciplinary team …
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Topologies and control estrategies of multiport modular multinivel converters
… ellos, los Convertidores Modulares Multinivel (MMC) constituyen una topología prometedora para aplicaciones que requieren un puerto de alta tensión DC. Los MMC, los cuales fueron presentados por primera vez hace una década, realizan una conversión DC/AC bidireccional. Comparten las …
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Evaluation of Markerless Motion Capture to Assess Physical Exposures During Material Handling Tasks
… accuracy of a markerless motion capture system (MMC) to quantify physical exposures during MMH tasks using three studies. Specifically, the first study investigated the performance of an MMC system, together with machine learning algorithms, for classifying diverse MMH tasks during a simulated …
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Switching-Cycle Control and Sensing Techniques for High-Density SiC-Based Modular Converters
… work. As the modular multilevel converter (MMC) is the most typical modular converter for high power applications, the research topic is narrowed down to study the SiC MOSFET-based MMC. Fundamentals of the MMC is firstly investigated by introducing a proposed state-space switching model, …
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