Blar i NTNU Open på forfatter "Røkke, Astrid"
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Additive Manufactured Amorphous Metal in High-Speed Interior Permanent Magnet Motor
Havnsund, Ulrik (Master thesis, 2020) -
Analysis of electromagnetic behavior of Permanent Magnetized (PM) electrical machines in fault modes
Hassan, Muhammad Usman (Master thesis, 2017)Over the years, the use of PM machines has been increasing in the offshore wind industry and marine industry. The industries thrive on efficient function of the PM machines. These machines are prone to electro-mechanical ... -
Analytical Calculation of Yoke Flux Patterns in Fractional-Slot Permanent Magnet Machines
Røkke, Astrid; Nilssen, Robert (Journal article; Peer reviewed, 2017)Machine design problems are often solved under the assumption of no-load when calculating iron flux densities. However, it is particularly important to account for the fluxes from the stator currents, the armature reaction, ... -
Design and measurement of a passive thrust magnetic bearing for a bearingless motor
Severson, Eric; Røkke, Astrid; Nilssen, Robert; Undeland, Tore Marvin; Mohan, Ned (IEEE Industrial Electronics Society. Annual Conference. Proceedings;IECON 2013, Journal article; Peer reviewed, 2013)The design and construction of a permanent magnet thrust bearing for a bearingless motor is presented and a measurement technique is proposed to characterize the bearing. Optimal design of a bearingless motor requires the ... -
Gradient based optimization of Permanent Magnet generator design for a tidal turbine
Røkke, Astrid (Chapter, 2014)An optimization of an analytical problem with nine variables is executed to find the optimal Permanent Magnet(PM) generator for a tidal turbine. A gradient based solver is used to find the minimum cost of active materials ... -
Investigating the Potential of Two Large Diameter Magnetic Bearings
Noddeland, Nils Børge Vaale; Røkke, Astrid (Master thesis, 2007)MAGNETIC bearings for large diameters and low rotational speeds are rarely developed and utilized due to poor competitive ability. They require little maintenance and offer high reliability, but until now mechanical bearings ... -
Marine Current Turbines and Generator preference. A technology review
Røkke, Astrid; Nilssen, Robert (Journal article; Peer reviewed, 2013)Marine current power is a significant energy resource yet to be exploited for electricity production. Several novel turbine technologies can be found on the market, and new ones emerge every year. This study found that the ... -
Maximum Torque Density Limit for Surface-Cooled SPM Machines
Bocchese, Andrea; Nøland, Jonas Kristiansen; Bianchi, Nicola; Noddeland, Børge; Røkke, Astrid (Chapter, 2020)The aim of this work is to find the maximum torque density limit of a surface cooled SPM machine. In this paper, an analytical and a FEM-based model are developed under some theoretical conditions. Both models consist of ... -
Optimal Design of Tidal Power Generator Using Stochastic Optimization Techniques
Engevik, Erlend L (Master thesis, 2014)Particle Swarm Optimization (PSO) and Genetic Algorithms (GA) are usedto reduce the cost of a permanent magnet synchronous generator with concentratedwindings for tidal power applications. Reducing the cost of the ... -
PERMANENT MAGNET GENERATORS FOR MARINE CURRENT TIDAL TURBINES
Røkke, Astrid (Doctoral theses at NTNU;2017:148, Doctoral thesis, 2017)The focus of this thesis is the design of a permanent magnet generator for a marine current turbine, more specifically a tidal turbine. Tidal turbines can offer a predictable input of energy to the power grid and help to ... -
Reducing sub-harmonic spatial fields in Concentrated winding machines using Genetic Algorithms
Nordaunet, Thomas (Master thesis, 2013)Certain slot/pole combinations in fractional slot winding machines with concentrated coils exhibit high amount of sub-harmonic spatial fields. These harmonics may cause additional losses and ripple torque. Literature suggest ... -
Simulation and Experimental Validation of Losses in Permanent-Magnet Synchronous Machines
Nordeide, Ivar Beseth (Master thesis, 2024)Permanent-magnet synkronmaskinen (PMSM) har vokst i popularitet, grunnet dens høye effekttetthet, virkningsgrad, effektfaktor og dens lave behov for kontroll og vedlikehold. Siden de første PMSM-ene kom, har det blitt gjort ...