middle loops.","permanent magnet machine; Concentrated winding; eddy current losses; experimental validation","en","conference paper","IEEE","978-1-4673-8863-4","","","","","","","","","DC systems, Energy conversion & Storage","","","" "uuid:c9c93b5e-64aa-4889-b5b3-ebe012e2b8f1","http://resolver.tudelft.nl/uuid:c9c93b5e-64aa-4889-b5b3-ebe012e2b8f1","Comparison of Levelized Cost of Energy of a 10 MW superconducting and magnetic pseudo direct drive generator targeted for the INNWIND.EU reference turbine","Abrahamsen, Asger Bech (Technical University of Denmark); Liu, D. (TU Delft DC systems, Energy conversion & Storage); Magnusson, Niklas (SINTEF); Thomas, A (Siemens Wind Power); Azar, Ziad (Siemens Wind Power); Stehouwer, Ewoud (DNV-GL); Hendriks, E (Knowledge Centre WMC); Penzkofer, A. (University of Sheffield); Atallah, K (University of Sheffield); Dragan, R.R. (Magnomatics); .Clark, R.E. (Magnomatics); Deng, F. (Aalborg University); Chen, Z (Aalborg University); Karwatzki, D. (Leibniz Universität); Mertens, A. (Leibniz Universität); Parker, Max (University of Strathclyde); Finney, Stephen J. (University of Strathclyde); Polinder, H.","","2017","Innovative drive trains targeted at 10-20 MW offshore turbines are investigated in the INNWIND.EU project in order to determine the impact on the Levelized Cost of Energy (LCoE) resulting when installed in the ,North sea at 50 m of water [1]. The two main technologies studied are superconducting direct drive (SCDD)[2] and the magnetic pseudo direct drive (PDD) [3] generators, which are both capable to providing compact drive trains with low weight and a small number of moving parts compared to a gearbox based drive train (see figure 1a). Superconducting field coils are used to provide the torque in the direct drive generators, where the armature windings are based on conventional copper wire and magnetic steel laminates operated at ambient temperature. Magnetic pseudo direct drive generators consist of a magnetic gearbox made of an inner free rotor (rotating at a geared up speed to the blade input) and an intermediate drive rotor inserted into an outer static armature winding, where the electricity is harvested.","","en","abstract","","","","","","","","","","","","","","" "uuid:624e0a6f-854f-463b-be4c-62af81f363ad","http://resolver.tudelft.nl/uuid:624e0a6f-854f-463b-be4c-62af81f363ad","Finite Element Analysis and Experimental Validation of Eddy Current Losses in Permanent Magnet Machines with Fractional-Slot Concentrated Windings","Wang, X. (TU Delft DC systems, Energy conversion & Storage); Liu, D. (TU Delft DC systems, Energy conversion & Storage); Lahaye, D.J.P. (TU Delft Numerical Analysis); Polinder, H. (TU Delft DC systems, Energy conversion & Storage); Ferreira, J.A. (TU Delft Electrical Power Processing)","","2016","Permanent-magnet machines with fractional slot concentrated windings are easy to manufacture. Their popularity therefore is steadily increasing. Without a proper design, however, the induced eddy-current losses in the solid rotor get rather high. The modeling and the prediction of eddy-current losses for these machines are thus very important during the design process. This paper focuses on the finite-element analysis and the experimental validation of eddy-current losses for this kind of machine with a small axial length. Two-dimensional and three-dimensional transient finite-element models are developed for computing the eddy-current losses. The rotor motion is taken into account using an Arbitrary Lagrangian-Eulerian formulation. The total iron losses are measured experimentally and a method to separate the rotor iron losses from the total iron losses is presented. The validation results show that the twodimensional finite-element model overestimates the losses due to the end-effects being neglected. The three-dimensional model agrees much better with the measurements in both no-load and on-load operations.","Concentrated winding; eddy current losses; experimental validation; permanent magnet machine","en","conference paper","IEEE","978-1-4673-8863-4","","","","","","","","","","","","" "uuid:98088329-676a-4ba0-b76e-4dfb48e4eb4e","http://resolver.tudelft.nl/uuid:98088329-676a-4ba0-b76e-4dfb48e4eb4e","Short Circuits of a 10 MW High Temperature Superconducting Wind Turbine Generator","Song, X. (Technical University of Denmark); Polinder, H. (TU Delft DC systems, Energy conversion & Storage); Liu, D. (TU Delft DC systems, Energy conversion & Storage); Mijatovic, Nenad (Technical University of Denmark); Holbøll, Joachim (Technical University of Denmark); Jensen, Bogi Bech (University of the Faroe Islands)","","2016","Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen at generator terminals. In this paper, a finite element model that couples magnetic fields and the generator’s equivalent circuits is developed to simulate short circuit faults. Afterwards, the model is used to study the transient performance of a 10 MW HTS wind turbine generator under four different short circuits, i.e., three-phase, phase-phase clear of earth, phase-phase-earth, and phase-earth. The stator current, fault torque, and field current under each short circuit scenario are examined. Also included are the forces experienced by the field winding under short circuits. The results show that the short circuits pose great challenges to the generator, and careful consideration should be given to protect the generator. The results presented in this paper would be beneficial to the design, operation and protection of an HTS wind turbine generator.","Finite element analysis; Force; High temperature superconducting generator; Short circuit; Transient","en","conference paper","IEEE","","","","","","","","","","","","","" "uuid:01387120-a39a-477f-acea-e5b902b018fa","http://resolver.tudelft.nl/uuid:01387120-a39a-477f-acea-e5b902b018fa","Design study of a 10 MW MgB2 superconductor direct drive wind turbine generator","Abrahamsen, A.B.; Magnusson, N.; Liu, D.; Stehouwer, E.; Hendriks, B.; Polinder, H.","","2014","A superconducting direct drive generator based on field windings of MgB2 superconducting tape is proposed as a solution by mounting the generator in front of the blades using a king-pin nacelle design for offshore turbines with power ratings larger than 10 MW as investigated in the INNWIND.EU project.","superconducting generator; direct drive generator; offshore wind turbine; nacelle integration","en","conference paper","EWEA","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electrical Sustainable Energy","","","","" "uuid:fabc0cb6-e868-4bf4-84c2-f45cfc7d6642","http://resolver.tudelft.nl/uuid:fabc0cb6-e868-4bf4-84c2-f45cfc7d6642","Design of an MgB2 race track coil for a wind generator pole demonstration","Abrahamsen, A.B.; Magnusson, N.; Jensen, B.B.; Liu, D.; Polinder, H.","","2014","An MgB2 race track coil intended for demonstrating a down scaled pole of a 10 MW direct drive wind turbine generator has been designed. The coil consists of 10 double pancake coils stacked into a race track coil with a cross section of 84 mm x 80 mm. The length of the straight section is 0.5 m and the diameter of the end sections is 0.3 m. Expanded to a straight section of 3.1 m it will produce about 1.5 T magnetic flux density in the air gap of the 10 MW 32 pole generator and about 3.0 T at the edge of the superconducting coil with an operation current density of the coil of 70 A/mm2.","","en","conference paper","IOP","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electrical Sustainable Energy","","","","" "uuid:42184015-8cac-4be2-8084-a221744d0452","http://resolver.tudelft.nl/uuid:42184015-8cac-4be2-8084-a221744d0452","Feasibility Study of a 10 MW MgB2 Fully Superconducting Generator for Offshore Wind Turbines","Kostopoulos, D.; Liu, D.; Genani, G.; Polinder, H.","","2013","Offshore wind is considered a vital component of the future large scale renewable generation portfolio. Intense R&D effort is occurring in both the technology and the supply chain aiming at cost reduction. The drivetrain of wind turbines is an area of continuous evolution with currently no one standard configuration in the industry. It is anticipated that in order to upscale offshore wind turbines in the 10+ MW power range innovation is necessary in this subsystem. A possible solution could be the adoption of superconductivity technology. The potential benefits are multiple comprising weight, dimension and cost reduction in both capital and operating costs. In this paper a rough analytical design is presented of an MgB2 fully superconducting wind turbine generator (WTG). An analytical current sheet distribution is adopted to calculate the magnetic field of the generator and a finite element method (FEM) analysis is used to verify the field calculation. The objective of this work is to assess the technical feasibility of this generator topology and attempt to extract more general conclusions regarding the potential application of superconducting drivetrains in offshore wind turbines.","","en","conference paper","European Wind Energy Association","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electrical Sustainable Energy","","","",""