In recent years, there has been a growing demand for high-power-density direct-drive generators in the wind industry owing to their high reliability, torque per unit volume, and conversion efficiencies. However, direct-drive wind turbine generators are very large, low-speed electric machines, which pose remarkable design and manufacturing issues that challenge their upscaling potential and cost of implementation. With air-gap tolerance as the main design driver, the need for high stiffness shifts the focus toward support-structure design that forms a significant portion of the generator’s total mass. Existing manufacturing processes allow the use of segmented-steel-weldment disk or spoke-arm assemblies that yield stiffer structures per unit mass but tend to be heavier and more expensive to build. As a result, there is a need for a transformative approach to realize lightweight designs that can also facilitate series production at competitive costs. Inspired by recent developments in metal additive manufacturing (AM), we explore a new freedom in the structural design space with a high potential for weight savings in direct-drive generators. This includes the feasibility of using nonconventional complex geometries, such as lattice-based structures as structurally efficient options. Powder-binder jetting of a sand-cast mold was identified as the most feasible AM technology to produce large-scale generator rotor structures with complex geometry. A parametric optimization study was performed and optimized results within deformation and mass constraints were found for each design. The response to the maximum Maxwell stress due to unbalanced magnetic pull was also explored for each design. Further, a topology optimization was applied for each parameter-optimized design to validate results and provide insights into further mass reduction. These novel designs catered for AM are compared in both deflection and mass to conventional rotor designs using NREL’s systems engineering design tool, GeneratorSE. The optimized lattice design with a U-beam truss resulted in a 24% reduction in structural mass of the rotor and 60% reduction in radial deflection. It is demonstrated that additive manufacturing shifts the focus from manufacturability constraints toward lower mass.
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ASME 2018 Power Conference collocated with the ASME 2018 12th International Conference on Energy Sustainability and the ASME 2018 Nuclear Forum
June 24–28, 2018
Lake Buena Vista, Florida, USA
Conference Sponsors:
- Power Division
- Advanced Energy Systems Division
- Solar Energy Division
- Nuclear Engineering Division
ISBN:
978-0-7918-5140-1
PROCEEDINGS PAPER
Additive Manufacturing: A New Paradigm for the Next Generation of High-Power-Density Direct-Drive Electric Generators
Austin C. Hayes,
Austin C. Hayes
Rochester Institute of Technology, Rochester, NY
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Latha Sethuraman,
Latha Sethuraman
National Renewable Energy Laboratory, Golden, CO
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Lee Jay Fingersh,
Lee Jay Fingersh
National Renewable Energy Laboratory, Golden, CO
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Katherine Dykes
Katherine Dykes
National Renewable Energy Laboratory, Golden, CO
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Austin C. Hayes
Rochester Institute of Technology, Rochester, NY
Latha Sethuraman
National Renewable Energy Laboratory, Golden, CO
Lee Jay Fingersh
National Renewable Energy Laboratory, Golden, CO
Katherine Dykes
National Renewable Energy Laboratory, Golden, CO
Paper No:
POWER2018-7140, V002T12A001; 16 pages
Published Online:
October 4, 2018
Citation
Hayes, AC, Sethuraman, L, Fingersh, LJ, & Dykes, K. "Additive Manufacturing: A New Paradigm for the Next Generation of High-Power-Density Direct-Drive Electric Generators." Proceedings of the ASME 2018 Power Conference collocated with the ASME 2018 12th International Conference on Energy Sustainability and the ASME 2018 Nuclear Forum. Volume 2: Heat Exchanger Technologies; Plant Performance; Thermal Hydraulics and Computational Fluid Dynamics; Water Management for Power Systems; Student Competition. Lake Buena Vista, Florida, USA. June 24–28, 2018. V002T12A001. ASME. https://doi.org/10.1115/POWER2018-7140
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