scholarly journals Electromechanical Dynamics Analysis of Pole-Piece Rotors in Pseudo Direct-Drive Wind Turbine Generators

Author(s):  
Michiel Desmedt ◽  
Jianning Dong ◽  
Faisal Wani ◽  
Pavol Bauer ◽  
Henk Polinder
2021 ◽  
Author(s):  
Austin C. Hayes ◽  
Gregory L. Whiting

Abstract Permanent magnet direct drive (PMDD) electric machines are advantageous due to higher efficiencies and lower maintenance concerns. For wind turbine generators, especially offshore turbines, this is advantageous to geared machines and is currently implemented by manufacturers such as GE, Siemens and Enercon. By nature, a direct drive machine must be larger than its geared counterpart in order to output the same power. As a result, the structural mass is larger and makes the machine prohibitively large. However, the structural mass and electromagnetic design is coupled and the electromagnetic criteria are an important consideration in the structural design. In this analysis, the electromagnetic design of a 5 MW PMDD generator was coupled to a triply periodic minimal surface (TPMS) lattice generator through means of an evolutionary algorithm. Finite element analysis (FEA) was used to determine the radial, torsional, and axial deformations under simulated wind turbine generator loading conditions subject to critical deflection criteria. Lattice functional grading was completed with the FEA deflection data in order to further optimize the structural mass. For the 5 MW test case, functional graded TPMS support structures maintained stiffness for a generator with a 32% higher force density with inactive mass 4% lower than baseline. This study suggests functional grading of TPMS lattice structures for wind turbine generators has the potential at significant mass savings.


Author(s):  
Austin C. Hayes ◽  
Gregory L. Whiting

Abstract Additive manufacturing enables the production of complex geometries extremely difficult to create with conventional subtractive methods. While good at producing complex parts, its limitations can be seen through its penetration into everyday manufacturing markets. Throughput limitations, poor surface roughness, limited material selection, and repeatability concerns hinder additive manufacturing from revolutionizing all but the low-volume, high-value markets. This work characterizes combining powder-binder jetting with traditional casting techniques to create large, complex metal parts. Specifically, we extend this technology to wind turbine generators and provide initial feasibility of producing complex direct-drive generator rotor and stator designs. In this process, thermal inkjet printer heads selectively deposit binder on hydroperm casting powder. This powder is selectively solidified and baked to remove moisture before being cast through traditional methods. This work identifies a scalable manufacturing process to print large-scale wind turbine direct drive generators. As direct-drive generators are substantially larger than their synchronous counterparts, a printing process must be able to be scaled for a 2–5 MW 2–6m machine. For this study, research on the powder, binder, and printing parameters is conducted and evaluated for scalability.


Author(s):  
Michael Kirschneck ◽  
Daniel J. Rixen ◽  
Henk Polinder ◽  
Ron A. J. van Ostayen

In large direct-drive off-shore wind turbine generators one challenge is to engineer the system to function securely with an air gap length of about a thousandth of the outer rotor diameter. Compared to the large diameter of the generator rotor, the rolling element bearings can only be constructed with a relatively limited size. This makes it challenging to design appropriate constructions able to transmit the large applied magnetic forces encountered in the air gap of direct drive wind turbine generators. Currently, this challenge is met by designing stiff heavy rotors that are able to withstand the forces in the air gap. Incorporating flexibility into the design of the rotor structure can lead to a lighter less expensive rotor. In order to be able to do this the magnetomechanical coupling in the air gap and its effect on the structural dynamics need to be taken into account when predicting the intended flexibility. This paper introduces an approach for a multiphysical modal analysis that makes it possible to predict the dynamics of the strongly coupled magnetomechanical system. The new method is validated using measurements of a simple lab setup. It is then applied to a single-bearing design direct-drive wind turbine generator rotor to calculate the changes of the structural dynamics caused by the electromagnetomechanical coupling.


Sign in / Sign up

Export Citation Format

Share Document