Sökning: "Multilevel systems"

Visar resultat 1 - 5 av 63 avhandlingar innehållade orden Multilevel systems.

  1. 1. Modular Battery Systems for Electric Vehicles based on Multilevel Inverter Topologies - Opportunities and Challenges

    Författare :Anton Kersten; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dynamic reconfiguration; Energy storage; Energy efficiency; Drive cycle efficiency; Power MOSFET; vehicles; H-bridge; Multilevel systems; Electromagnetic compatibility; Modular battery systems; Battery system performance; Modular multilevel converters; Conduction losses; Electric vehicles; Batteries; Dual battery pack; Cascaded converters; DC-AC power converters; BMS; Common mode noise; Battery modeling; vehicle electrification;

    Sammanfattning : Modular battery systems based on multilevel inverter (MLI) topologies can possibly overcome some shortcomings of two-level inverters when used for vehicle propulsion. The results presented in this thesis aim to point out the advantages and disadvantages, as well as the technical challenges, of modular vehicle battery systems based on MLIs in comparison to a conventional, two-level IGBT inverter drivetrain. LÄS MER

  3. 2. Voters' Perceptions of Party Politics - A Multilevel Approach

    Författare :Stefan Dahlberg; Göteborgs universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Policy representation; voter perceptions; voting behavior; left-right ideology; perceptual agreement; political parties; party systems; electoral systems; institutions; multilevel;

    Sammanfattning : Modern representative democracies are often described as government by the consent of the governed rather than government by the people. Elections play a central role in this context and several theorists of modern democracy have struggled to determine the circumstances under which effective political representation can exist. LÄS MER

  4. 3. Emerging networks of power: Exploring sociotechnical pathways towards future electricity systems based on renewable energy technologies

    Författare :Kristina Hojcková; Chalmers tekniska högskola; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; entrepreneurs; context; sociotechnical systems perspective; Technological Innovation System; Multilevel Perspective; electricity system; transition pathways; incumbents; renewable energy; energy users;

    Sammanfattning : In the effort to fight climate change, electricity systems around the world are undergoing a transition from fossil-fuelled to renewable energy-based production of electricity. The transition can, however, be attained in several radically different ways, ranging from global or continental super-grids, via local smart-grids, to self-sufficient off-grid communities and households of electricity prosumers. LÄS MER

  5. 4. Thermal and State-of-Charge Balancing of Batteries using Multilevel Converters

    Författare :Faisal Altaf; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thermal balancing; Convex optimization; DC-link ripple; Battery ripple; Battery control; Hybrid electric vehicles.; Multilevel converter; Cell balancing;

    Sammanfattning : Driven by the needs to reduce the dependence of fossil fuels and the emissions of conventional vehicles there has in recent years been an increasing interest in battery-powered electrified vehicles (xEVs). In xEVs, the battery pack, built from many small cells, is one of the most expensive components in the powertrain. LÄS MER

  7. 5. Modulation, efficiency and lifetime of two-level and multilevel converters for a hydropower application

    Författare :Chengjun Tang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Pumped-storage hydropower; pulse width modulation; losses; modular multilevel converter; efficiency; variable speed; converter; lifetime; space vector modulation; thermal modelling; neutral point clamped converter;

    Sammanfattning : Along with the integration of the renewable energy in the electrical grid, the pumped-storage hydropower has gained more and more attention due to its fast response and energy storage ability. To have a higher overall efficiency and more flexibility of the system, variable speed is preferred in the operation of the pumped-storage hydropower applications. LÄS MER