Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control
A wave-energy converter has been studied through the combination of laboratory experiments and numerical simulations. The converter model is a semi-submerged axi-symmetric buoy with a circular cross section with a diameter of 26 cm at the water plane. The buoy is pitching about a fixed external axis...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-09-01
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| Series: | Energies |
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| Online Access: | http://www.mdpi.com/1996-1073/11/9/2362 |
| _version_ | 1811262956323733504 |
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| author | Amélie Têtu Francesco Ferri Morten Bech Kramer Jørgen Hals Todalshaug |
| author_facet | Amélie Têtu Francesco Ferri Morten Bech Kramer Jørgen Hals Todalshaug |
| author_sort | Amélie Têtu |
| collection | DOAJ |
| description | A wave-energy converter has been studied through the combination of laboratory experiments and numerical simulations. The converter model is a semi-submerged axi-symmetric buoy with a circular cross section with a diameter of 26 cm at the water plane. The buoy is pitching about a fixed external axis oriented such that the buoy works primarily in heave. The laboratory model is equipped with a spring mechanism referred to as WaveSpring, which works to shift the resonance period and increase the response bandwidth of the system. A controlled electric actuator was connected and programmed to provide a velocity-proportional force for power extraction. The buoy mass was varied at two levels and the experimental setup was exposed to a selection of regular and irregular waves. The power take-off (PTO) damping was set as a function of sea state. A mathematical model for global motion response was developed based on linear hydrodynamic theory and rigid-body dynamics. Comparison of laboratory measurements and numerical simulation results shows that the dominant physical effects have been well captured by the mathematical model. Overall, the study gives an experimental verification that a negative spring mechanism mounted in parallel with the power take-off machinery of a wave energy converter may be used to increase the average converted power. |
| first_indexed | 2024-04-12T19:36:11Z |
| format | Article |
| id | doaj.art-3b6b602de0fa443e83a392cdcd4a165b |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-12T19:36:11Z |
| publishDate | 2018-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-3b6b602de0fa443e83a392cdcd4a165b2022-12-22T03:19:12ZengMDPI AGEnergies1996-10732018-09-01119236210.3390/en11092362en11092362Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase ControlAmélie Têtu0Francesco Ferri1Morten Bech Kramer2Jørgen Hals Todalshaug3Department of Civil Engineering, Aalborg University, DK-9220 Aalborg, DenmarkDepartment of Civil Engineering, Aalborg University, DK-9220 Aalborg, DenmarkDepartment of Civil Engineering, Aalborg University, DK-9220 Aalborg, DenmarkDepartment of Marine Technology, Norwegian University of Science and Technology (NTNTU), NO-7491 Trondheim, NorwayA wave-energy converter has been studied through the combination of laboratory experiments and numerical simulations. The converter model is a semi-submerged axi-symmetric buoy with a circular cross section with a diameter of 26 cm at the water plane. The buoy is pitching about a fixed external axis oriented such that the buoy works primarily in heave. The laboratory model is equipped with a spring mechanism referred to as WaveSpring, which works to shift the resonance period and increase the response bandwidth of the system. A controlled electric actuator was connected and programmed to provide a velocity-proportional force for power extraction. The buoy mass was varied at two levels and the experimental setup was exposed to a selection of regular and irregular waves. The power take-off (PTO) damping was set as a function of sea state. A mathematical model for global motion response was developed based on linear hydrodynamic theory and rigid-body dynamics. Comparison of laboratory measurements and numerical simulation results shows that the dominant physical effects have been well captured by the mathematical model. Overall, the study gives an experimental verification that a negative spring mechanism mounted in parallel with the power take-off machinery of a wave energy converter may be used to increase the average converted power.http://www.mdpi.com/1996-1073/11/9/2362point absorbernegative springrenewable ocean energypower take-offhydrostatic stiffnessphase control |
| spellingShingle | Amélie Têtu Francesco Ferri Morten Bech Kramer Jørgen Hals Todalshaug Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control Energies point absorber negative spring renewable ocean energy power take-off hydrostatic stiffness phase control |
| title | Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control |
| title_full | Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control |
| title_fullStr | Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control |
| title_full_unstemmed | Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control |
| title_short | Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control |
| title_sort | physical and mathematical modeling of a wave energy converter equipped with a negative spring mechanism for phase control |
| topic | point absorber negative spring renewable ocean energy power take-off hydrostatic stiffness phase control |
| url | http://www.mdpi.com/1996-1073/11/9/2362 |
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