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Hagmuller, Alex

Publications and source records attributed to Hagmuller, Alex.

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A Multi-Stack Variable Stiffness Magnetic Torsion Spring for a Wave Energy Converter

This paper presents the design of a multi-stack high torque adjustable stiffness torsional magnetic spring for use in a wave energy converter. The torsional magnetic spring has a ±45 degrees linear stroke length with peak torque of 823 N⋅m. A 3-D magnetostatic finite element analysis parameter sizing sweeping analysis was performed and the peak energy density for the selected torsion spring was computed to be 12.6 J/kg. The required torque was increased by using a unique seven-stage multi-stacking design. The stiffness of magnetic torsion spring is adjusted through the axial translation of the inner rotor. The presented design is shown to be capable of providing both positive and negative stiffness with equal characteristics and has a very high degree of linearity. The experimental prototype assembly and test-setup used to verify the torsional spring performance is presented.

16 TIDAL AND WAVE POWER↗
DOE OSTI2021

TEAMER - AquaHarmonics High Fidelity WEC Sim PTO and Control Model Validation, Test Logs and Results

Collaborative effort between AquaHarmonics, Sandia National Laboratories (SNL), and the National Renewable Energy Laboratory (NREL) to revise and validate Aquaharmonics' full wave to wire model, allowing for reduced uncertainty and increased understanding of design requirements of a utility scale wave energy converter (WEC). SNL and NREL in collaboration with AquaHarmonics, will set up and run WEC Simulator (WEC-Sim) models of the AquaHarmonics WEC, building off past model developments for inclusion of custom PTO (power take-off) dynamics. The intent is to review, update, and verify or validate a new WEC-Sim model against wave tank experimental data. Furthermore, the WEC-Sim model will be coupled to an energy storage system model to better understand the wave-to-wire functionality. This data set is described in the "Test Log" excel file. Please refer to that document for details on each specific test date/time, constraint parameters and model hardware setup details. Sim model can be found in the associated MHKDR link below.

16 TIDAL AND WAVE POWER↗
DOE OSTI2021

An Adjustable Stiffness Torsional Magnetic Spring with a Linear Stroke Length

This paper presents the analysis, mechanical design, and proof-of-principle experimental testing of a new type of adjustable stiffness torsional magnetic spring for an ocean generator application. Unlike prior published designs the rotary magnetic spring is shown to have a highly linear adjustable stroke length. The presented torsional spring is experimentally shown to be able to create a ± 45° angular stroke range with a peak torque of ± 39.1 N·m. The stiffness is adjusted by using a stepper motor to axially adjust the axial magnet offset. The stepper motor contains a brake so that power is not expended when maintaining a desired spring stiffness. It is shown that by using a series spring arrangement the stroke length can be extended to ± 90°.

16 TIDAL AND WAVE POWER↗