### Abstract

Original language | English |
---|---|

Article number | 2362 |

Journal | Energies |

Volume | 11 |

Issue number | 9 |

ISSN | 1996-1073 |

DOIs | |

Publication status | Published - 7 Sep 2018 |

### Fingerprint

### Keywords

- Renewable ocean energy
- Phase control
- Negative spring
- Point absorber
- Hydrostatic stiffness
- Power take-off

### Cite this

*Energies*,

*11*(9), [2362]. https://doi.org/10.3390/en11092362

}

*Energies*, vol. 11, no. 9, 2362. https://doi.org/10.3390/en11092362

**Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control.** / Tetu, Amélie; Ferri, Francesco; Kramer, Morten Mejlhede; Hals Todalshaug, Jørgen.

Research output: Contribution to journal › Journal article › Research › peer-review

TY - JOUR

T1 - Physical and Mathematical Modeling of a Wave Energy Converter Equipped with a Negative Spring Mechanism for Phase Control

AU - Tetu, Amélie

AU - Ferri, Francesco

AU - Kramer, Morten Mejlhede

AU - Hals Todalshaug, Jørgen

PY - 2018/9/7

Y1 - 2018/9/7

N2 - 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.

AB - 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.

KW - Renewable ocean energy

KW - Phase control

KW - Negative spring

KW - Point absorber

KW - Hydrostatic stiffness

KW - Power take-off

KW - Renewable ocean energy

KW - Phase control

KW - Negative spring

KW - Point absorber

KW - Hydrostatic stiffness

KW - Power take-off

U2 - 10.3390/en11092362

DO - 10.3390/en11092362

M3 - Journal article

VL - 11

JO - Energies

JF - Energies

SN - 1996-1073

IS - 9

M1 - 2362

ER -