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1.
公开(公告)号:US20180163691A1
公开(公告)日:2018-06-14
申请号:US15837885
申请日:2017-12-11
申请人: Ossama Abdelkhalik , Rush D. Robinett, III , Shangyan Zou , Umesh Korde , National Technology & Engineering Solutions of Sandia, LLC
发明人: Ossama Abdelkhalik , Rush D. Robinett, III , Shangyan Zou , David G. Wilson , Giorgio Bacelli , Umesh Korde , Ryan G. Coe
CPC分类号: F03B13/183 , F03B13/16 , F03B15/00 , F05B2250/43 , F05B2270/20 , G06F1/02 , G06F1/022 , Y02E10/38
摘要: A parametric excitation dynamic model is used for a three degrees-of-freedom (3-DOF) wave energy converter. Since the heave motion is uncoupled from the pitch and surge modes, the pitch-surge equations of motion can be treated as a linear time varying system, or a linear system with parametric excitation. In such case the parametric exciting frequency can be tuned to twice the natural frequency of the system for higher energy harvesting. A parametric excited 3-DOF wave energy converter can harvest more power, for both regular and irregular waves, compared to the linear 3-DOF. For example, in a Bretschneider wave, the harvested energy in the three modes is about 3.8 times the energy harvested in the heave mode alone; while the same device produces about 3.1 times the heave mode energy when using a linear 3-DOF model.
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公开(公告)号:US20180164755A1
公开(公告)日:2018-06-14
申请号:US15830770
申请日:2017-12-04
申请人: Ossama Abdelkhalik , Shangyan Zou , Rush D. Robinett, III , Umesh Korde , National Technology & Engineering Solutions of Sandia, LLC
发明人: Ossama Abdelkhalik , Shangyan Zou , Rush D. Robinett, III , David G. Wilson , Giorgio Bacelli , Ryan Geoffrey Coe , Umesh Korde
CPC分类号: G05B11/38 , F03B13/16 , F03B13/22 , F03B15/00 , F05B2240/93 , F05B2250/231 , F05B2250/241 , F05B2250/43 , F05B2270/20 , G06F17/142 , Y02E10/38
摘要: Multi-resonant control of a 3 degree-of-freedom (heave-pitch-surge) wave energy converter enables energy capture that can be in the order of three times the energy capture of a heave-only wave energy converter. The invention uses a time domain feedback control strategy that is optimal based on the criteria of complex conjugate control. The multi-resonant control can also be used to shift the harvested energy from one of the coupled modes to another, enabling the elimination of one of the actuators otherwise required in a 3 degree-of-freedom wave energy converter. This feedback control strategy does not require wave prediction; it only requires the measurement of the buoy position and velocity.
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公开(公告)号:US20180163690A1
公开(公告)日:2018-06-14
申请号:US15837853
申请日:2017-12-11
申请人: Ossama Abdelkhalik , Shangyan Zou , Rush D. Robinett, III , National Technology & Engineering Solutions of Sandia, LLC
发明人: Ossama Abdelkhalik , Giorgio Bacelli , Shangyan Zou , Rush D. Robinett, III , David G. Wilson , Ryan G. Coe
CPC分类号: F03B13/183 , F03B13/16 , F03B15/00 , F03B15/20 , F05B2250/43 , F05B2270/20 , G02F1/39 , G06F1/02 , G06F1/022 , H01J49/4275 , Y02E10/38
摘要: The invention provides optimal control of a three-degree-of-freedom wave energy converter using a pseudo-spectral control method. The three modes are the heave, pitch and surge. A dynamic model is characterized by a coupling between the pitch and surge modes, while the heave is decoupled. The heave, however, excites the pitch motion through nonlinear parametric excitation in the pitch mode. The invention can use a Fourier series as basis functions to approximate the states and the control. For the parametric excited case, a sequential quadratic programming approach can be implemented to numerically solve for the optimal control. The numerical results show that the harvested energy from three modes is greater than three times the harvested energy from the heave mode alone. Moreover, the harvested energy using a control that accounts for the parametric excitation is significantly higher than the energy harvested when neglecting this nonlinear parametric excitation term.
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公开(公告)号:US10423126B2
公开(公告)日:2019-09-24
申请号:US15830752
申请日:2017-12-04
申请人: National Technology & Engineering Solutions of Sandia, LLC , Rush D. Robinett, III , Ossama Abdelkhalik , Jiajun Song
摘要: A multi-resonant wide band controller decomposes the wave energy converter control problem into sub-problems; an independent single-frequency controller is used for each sub-problem. Thus, each sub-problem controller can be optimized independently. The feedback control enables actual time-domain realization of multi-frequency complex conjugate control. The feedback strategy requires only measurements of the buoy position and velocity. No knowledge of excitation force, wave measurements, nor wave prediction is needed. As an example, the feedback signal processing can be carried out using Fast Fourier Transform with Hanning windows and optimization of amplitudes and phases. Given that the output signal is decomposed into individual frequencies, the implementation of the control is very simple, yet generates energy similar to the complex conjugate control.
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公开(公告)号:US20180164754A1
公开(公告)日:2018-06-14
申请号:US15830752
申请日:2017-12-04
申请人: Rush D. Robinett, III , Ossama Abdelkhalik , Jiajun Song , National Technology & Engineering Solutions of Sandia, LLC
摘要: A multi-resonant wide band controller decomposes the wave energy converter control problem into sub-problems; an independent single-frequency controller is used for each sub-problem. Thus, each sub-problem controller can be optimized independently. The feedback control enables actual time-domain realization of multi-frequency complex conjugate control. The feedback strategy requires only measurements of the buoy position and velocity. No knowledge of excitation force, wave measurements, nor wave prediction is needed. As an example, the feedback signal processing can be carried out using Fast Fourier Transform with Hanning windows and optimization of amplitudes and phases. Given that the output signal is decomposed into individual frequencies, the implementation of the control is very simple, yet generates energy similar to the complex conjugate control.
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公开(公告)号:US10344736B2
公开(公告)日:2019-07-09
申请号:US15837853
申请日:2017-12-11
发明人: Ossama Abdelkhalik , Giorgio Bacelli , Shangyan Zou , Rush D. Robinett, III , David G. Wilson , Ryan G. Coe
IPC分类号: F03B13/10 , F03B13/12 , F03B13/18 , F03B15/20 , G02F1/39 , G06F1/02 , H01J49/42 , F03B13/16 , F03B15/00
摘要: The invention provides optimal control of a three-degree-of-freedom wave energy converter using a pseudo-spectral control method. The three modes are the heave, pitch and surge. A dynamic model is characterized by a coupling between the pitch and surge modes, while the heave is decoupled. The heave, however, excites the pitch motion through nonlinear parametric excitation in the pitch mode. The invention can use a Fourier series as basis functions to approximate the states and the control. For the parametric excited case, a sequential quadratic programming approach can be implemented to numerically solve for the optimal control. The numerical results show that the harvested energy from three modes is greater than three times the harvested energy from the heave mode alone. Moreover, the harvested energy using a control that accounts for the parametric excitation is significantly higher than the energy harvested when neglecting this nonlinear parametric excitation term.
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公开(公告)号:US10823134B2
公开(公告)日:2020-11-03
申请号:US16534746
申请日:2019-08-07
IPC分类号: F03B13/14
摘要: The present invention is directed to a nonlinear controller for nonlinear wave energy converters (WECs). As an example of the invention, a nonlinear dynamic model is developed for a geometrically right-circular cylinder WEC design for the heave-only motion, or a single degree-of-freedom (DOF). The linear stiffness term is replaced by a nonlinear cubic hardening spring term to demonstrate the performance of a nonlinear WEC as compared to an optimized linear WEC. By exploiting the nonlinear physics in the nonlinear controller, equivalent power and energy capture, as well as simplified operational performance is observed for the nonlinear cubic hardening spring controller when compared to an optimized linear controller.
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公开(公告)号:US10197040B2
公开(公告)日:2019-02-05
申请号:US15466605
申请日:2017-03-22
申请人: National Technology & Engineering Solutions of Sandia, LLC , Michigan Technological University , South Dakota Board of Regents
发明人: Ossama Abdelkhalik , Rush D. Robinett, III , Shangyan Zou , Giorgio Bacelli , David G. Wilson , Umesh Korde
IPC分类号: F03B13/16 , G05B19/406 , F03B15/00
摘要: A wave energy converter and method for extracting energy from water waves maximizes the energy extraction per cycle by estimating an excitation force of heave wave motion on the buoy, computing a control force from the estimated excitation force using a dynamic model, and applying the computed control force to the buoy to extract energy from the heave wave motion. Analysis and numerical simulations demonstrate that the optimal control of a heave wave energy converter is, in general, in the form of a bang-singular-bang control; in which the optimal control at a given time can be either in the singular arc mode or in the bang-bang mode. The excitation force and its derivatives at the current time can be obtained through an estimator, for example, using measurements of pressures on the surface of the buoy in addition to measurements of the buoy position. A main advantage of this approximation method is the ease of obtaining accurate measurements for pressure on the buoy surface and for buoy position, compared to wave elevation measurements.
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9.
公开(公告)号:US10415537B2
公开(公告)日:2019-09-17
申请号:US15837885
申请日:2017-12-11
申请人: National Technology & Engineering Solutions of Sandia, LLC , Michigan Technological University , South Dakota Board of Regents
发明人: Ossama Abdelkhalik , Rush D. Robinett, III , Shangyan Zou , David G. Wilson , Giorgio Bacelli , Umesh Korde , Ryan G. Coe
摘要: A parametric excitation dynamic model is used for a three degrees-of-freedom (3-DOF) wave energy converter. Since the heave motion is uncoupled from the pitch and surge modes, the pitch-surge equations of motion can be treated as a linear time varying system, or a linear system with parametric excitation. In such case the parametric exciting frequency can be tuned to twice the natural frequency of the system for higher energy harvesting. A parametric excited 3-DOF wave energy converter can harvest more power, for both regular and irregular waves, compared to the linear 3-DOF. For example, in a Bretschneider wave, the harvested energy in the three modes is about 3.8 times the energy harvested in the heave mode alone; while the same device produces about 3.1 times the heave mode energy when using a linear 3-DOF model.
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公开(公告)号:US11326574B2
公开(公告)日:2022-05-10
申请号:US16792749
申请日:2020-02-17
发明人: David G. Wilson , Giorgio Bacelli , Ryan Geoffrey Coe , Rush D. Robinett, III , Ossama Abdelkhalik
摘要: Increased energy harvesting is realized using a nonlinear buoy geometry for reactive power generation. By exploiting the nonlinear dynamic coupling between the buoy geometry and the potential wideband frequency spectrum of incoming waves in the controller/buoy design, increased power can be captured in comparison to conventional wave energy converter designs. In particular, the reactive power and energy storage system requirements are inherently embedded in the nonlinear buoy geometry, therefore requiring only simple rate-feedback control.
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