Browsing Institutt for elkraftteknikk by Document Types "Doctoral thesis"
Now showing items 21-40 of 126
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Design and optimisation of an auxiliary power supply with medium-voltage isolation using GaN HEMTs
(Doctoral theses at NTNU;2020:350, Doctoral thesis, 2020)This PhD thesis shows that compact and efficient converter systems can be obtained by leveraging the inherent characteristics of GaN HEMT devices. In the targeted application of an auxiliary power supply with medium-voltage ... -
Design of Large Permanent Magnetized Synchronous Electric Machines: Low Speed, High Torque Machiines - Gererator for Diriect Driven Wind Turbine- Motor for Rim Driven Thruster
(Doktoravhandlinger ved NTNU, 1503-8181; 2011:25, Doctoral thesis, 2011)This work presents the design of two prototype permanent magnetized electric machines for two different applications where large permanent magnet machines might be used. Existing technology have been used as the fundament ... -
DESIGN, OPERATION AND CONTROL OF SERIES-CONNECTED POWER CONVERTERS FOR OFFSHORE WIND PARKS
(Doctoral Theses at NTNU, 1503-8181, Doctoral thesis, 2012)OFFSHORE wind farms need to develop technologies that fulfill three main objectives:Efficiency, power density and reliability. The purpose of this thesisis to study an HVDC transmission system based on series connection ... -
Designing grid tariffs and local electricity markets for peak demand reduction in distribution grids
(Doctoral theses at NTNU;2022:394, Doctoral thesis, 2022)The decarbonization of the power system is envisioned to be a key part of European Union’s goal to be climate neutral by 2050. By shifting from large fossil fuel generation to climate-friendly renewable energy sources, ... -
Dielectric barriers under lightning impulse stress: Breakdown and discharge-dielectric interaction in short non-uniform air gaps
(Doctoral theses at NTNU;2019:106, Doctoral thesis, 2019)Dielectric-air insulation systems can reduce the carbon footprint of medium voltage switchgear, as they can replace SF6-insulated systems. Such replacement is, however, not easy, as the devices are typically compact and ... -
Digital Control of Converters for Distributed Power Generations
(Doktoravhandlinger ved NTNU, 1503-8181; 2008:82, Doctoral thesis, 2008)Pulse width modulated converters are becoming increasingly popular as their cost decreases and power rating increases. The new trend of smallscale power producers, often using renewable energy sources, has created new ... -
Dynamic analysis and monitoring of power transmission cables using fibre optic sensors
(Doktoravhandlinger ved NTNU, 1503-8181; 2005:203, Doctoral thesis, 2005)Aeolian vibration is a well known phenomen that can occur on overhead power lines in light to moderate steady winds. The amplitude of these vibrations is usually less than the conductor diameter, while the frequency, ... -
Dynamic Electricity Market Games – Modeling Competition under Large-scale Storage
(Doctoral theses at NTNU;2019:177, Doctoral thesis, 2019)Electricity shows similar characteristics to traditional commodity goods which led to the market mechanisms to trade electricity being developed in similar manner to markets for other commodities. Kirchho's laws, however, ... -
Earth Fault Location in Non-Radial Resonant Grounded Networks – Theory, analysis and methods
(Doctoral theses at NTNU;2024:59, Doctoral thesis, 2024)A common grounding scheme for medium voltage distribution networks and high voltage sub-transmission networks is the resonance grounding scheme. Resonant grounded networks have few interruptions and a high quality of supply, ... -
Effect of Absorbed Water and Temperature on Charge Transport and Accumulation in XLPE Cable Insulation
(Doctoral theses at NTNU;2021:243, Doctoral thesis, 2021)As the use of HVDC subsea power cables increases, studying DC phenomena in wet conditions becomes increasingly important. Space charge accumulation and transport in the insulation is relevant for ageing and the ability to ... -
Electric Traction Power System Stability: Low-frequency interaction between advanced rail vehicles and a rotary frequency converter
(Doktoravhandlinger ved NTNU, 1503-8181; 2010:56, Doctoral thesis, 2010)Low-frequency instability in AC electric traction power systems has come to be a concern in recent years. Power oscillations in the range of 10-30 % of the system’s fundamental frequency are reported from all over the world ... -
Electrical and Thermal Ageing of Extruded Low Density Polyethylene Insulation Under HVDC Conditions
(Dr. ingeniøravhandling, 0809-103X; 2000:125, Doctoral thesis, 2000)After extensive research during the last decades extruded polymeric insulation is now becoming an alternative to the traditional oil-paper systems for high voltage DC (HVDC) cables. Durability is of great importance for ... -
Electromagnetic field calculation and power loss evaluation in power transformers - Analysis of Leakage Fields and Stray Losses under Special Operation Conditions
(Doctoral theses at NTNU;2022:395, Doctoral thesis, 2022)The PhD research work presented in this thesis deals with electromagnetic field calculation and loss evaluation in power transformers under special operation conditions. The special loading conditions under investigation ... -
Energy management systems on board of electric vehicles, based on power electronics
(Doctoral Theses at NTNU, 1503-8181; 2009:38, Doctoral thesis, 2009)The core of any electric vehicle (EV) is the electric drive train, intended as the energy conversion chain from the energy tank (typically some kind of rechargeable battery) to the electric motor that converts the electrical ... -
Energy savings in road lighting: Correct lighting at all times and every condition
(Doctoral Theses at NTNU, 1503-8181; 2013:252, Doctoral thesis, 2013)Through field-, laboartory- and teoretichal potential-studies. The available energy savings potential in norwegian street- and roadlighting installations of today has been found. -
Energy Storage for Control of Distributed Photovoltaic Power Systems
(Doctoral theses at NTNU;2019:15, Doctoral thesis, 2019)The residential energy storage market is growing at a rapid pace in many countries. Increasing the consumption of locally produced energy and the use of energy storage as a backup source have been the main reasons for ... -
Enhanced Sensorless Control of Electric Drivetrains for Deep-Sea Mining Vehicles: Equipped with Three-Phase and Six-Phase IPMSM
(Doctoral theses at NTNU;2023:193, Doctoral thesis, 2023)The thesis deals with sensorless control methods for three-phase and six-phase Interior PermanentMagnet SynchronousMachine (IPMSM) drives, targeted for deep-sea mining vehicles (DMVs). Rapid growth in the demand for earth ... -
Environmental constraints in stochastic hydropower scheduling for long planning horizons
(Doctoral theses at NTNU;2023:211, Doctoral thesis, 2023)The transformation of the European power system to a climate-friendly one by 2050 involves a shift from fossil fuel generation to renewable energy sources. As a part of this transition, flexible assets are needed to balance ... -
Evaluation and Grouping of Power Market Scenarios in Security of Electricity Supply Analysis
(Doktoravhandlinger ved NTNU, 1503-8181; 2014:85, Doctoral thesis, 2014)In power system reliability assessment, at the transmission system level, a basic requirement of the analysis is models describing load and generation profiles at the individual buses, as these variables are needed as input ... -
Evaluation, Modeling and Control of Modular Multilevel Converter for Photovoltaic Applications
(Doctoral theses at NTNU;2019:193, Doctoral thesis, 2019)