Enhanced power absorption of a point absorber wave energy converter using a tuned inertial mass

Haraguchi, Ruriko; Asai, Takahiro

doi:10.1016/j.energy.2020.117740

Cited by 35 publications

(14 citation statements)

References 32 publications

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“…To improve the power generation performance of a conventional singlebody point absorber WEC, which has one floating buoy, the authors employed a tuned inerter mechanism [14,15]. Originally, the tuned inerter mechanism was proposed by [16] as a structural control device to absorb vibration energy effectively from vibrating civil structures such as buildings induced by seismic disturbances and to mitigate damage.…”

Section: Introductionmentioning

confidence: 99%

“…The authors employed a generator or a motor as the linear damping element in the tuned inerter mechanism and showed that the mechanism enhances the ability to extract energy from vibrating structures at a low frequency of less than 10 Hz [18,19]. In addition, the authors proposed a single-body point absorber WEC with a tuned inerter and the efficacy of the present device was shown through numerical simulation studies [14] and wave flume testing using a small-scale prototype model [15]. However, generally, the single-body point absorber WEC needs to be connected directly to the ocean floor.…”

Section: Introductionmentioning

confidence: 99%

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Numerical evaluation of a two-body point absorber wave energy converter with a tuned inerter

Asai

Sugiura

2021

Renewable Energy

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To increase the amount of energy captured from a vibrating buoy in the ocean with a simple mechanism, this paper proposes a two-body point absorber wave energy converter (WEC) with a tuned inerter. The tuned inerter mechanism consists of a spring, a linear damping element, and a component called inerter. This mechanism was originally proposed in the field of civil engineering as a structural control device which can absorb energy from vibrating structures effectively by taking advantage of the resonance effect of the inerter part. In addition to this mechanism where a generator is used as the linear damping element, the current of the generator for the power take-off system is controlled based on the algorithms proposed in literature to achieve further improvement of the power generation capability. In this research, a detailed analytical model of the proposed WEC is introduced and developed. Then the power generation performances of full-scale WEC models are assessed through numerical simulation studies using WAMIT software and it is shown that the current-controlled WEC with the proposed mechanism achieves an 88% increase compared to the conventional one for the JONSWAP spectrum with 6 s peak period and 1 m significant wave height.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical evaluation of a two-body point absorber wave energy converter with a tuned inerter

Asai

Sugiura

2021

Renewable Energy

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“…A self-sensing harvester, which measures temperature [ 3 ], displacement [ 4 ], and body motions [ 5 ] without the use of specific sensors and batteries, has also been proposed for advanced applications. Transducers for vibration energy harvesting include tuned mass dampers [ 6 , 7 ], magneto-rheological elastomers [ 8 ], electromagnetic devices [ 9 , 10 ], electrets [ 11 , 12 ], magnetostrictive elements [ 13 , 14 , 15 ], and piezoelectric elements [ 16 ]. Piezoelectric transducers convert mechanical energy into electrical energy and vice versa as direct and inverse piezoelectric effects [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Adaptive and Robust Operation with Active Fuzzy Harvester under Nonstationary and Random Disturbance Conditions

Hara

Otsuka

Makihara

2021

Sensors

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The objective of this paper is to amplify the output voltage magnitude from a piezoelectric vibration energy harvester under nonstationary and broadband vibration conditions. Improving the transferred energy, which is converted from mechanical energy to electrical energy through a piezoelectric transducer, achieved a high output voltage and effective harvesting. A threshold-based switching strategy is used to improve the total transferred energy with consideration of the signs and amplitudes of the electromechanical conditions of the harvester. A time-invariant threshold cannot accomplish effective harvesting under nonstationary vibration conditions because the assessment criterion for desirable control changes in accordance with the disturbance scale. To solve this problem, we developed a switching strategy for the active harvester, namely, adaptive switching considering vibration suppression-threshold strategy. The strategy adopts a tuning algorithm for the time-varying threshold and implements appropriate intermittent switching without pre-tuning by means of the fuzzy control theory. We evaluated the proposed strategy under three realistic vibration conditions: a frequency sweep, a change in the number of dominant frequencies, and wideband frequency vibration. Experimental comparisons were conducted with existing strategies, which consider only the signs of the harvester electromechanical conditions. The results confirm that the presented strategy achieves a greater output voltage than the existing strategies under all nonstationary vibration conditions. The average amplification rate of output voltage for the proposed strategy is 203% compared with the output voltage by noncontrolled harvesting.

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“…The semi-active inerter (SAI) is a kind of inerter whose inertance can be adjusted online (Chen et al, 2014;Hu et al, 2017). The performance benefits of applying an inerter in various mechanical systems have been demonstrated including the vehicle suspensions (Hu et al, 2018b;Liu et al, 2020a;Shen et al, 2018), wind turbines (Hu et al, 2018a;Li et al, 2020b;Zhang et al, 2019a), buildings (De Domenico et al, 2019, 2020Luo et al, 2017;Zhang et al, 2018Zhang et al, , 2019b, energy harvesting systems (Liu et al, 2020b;Petrini et al, 2020;Zhu et al, 2019), WECs Buckham, 2018, 2020;Haraguchi and Asai, 2020;Li et al, 2020a), etc. For the application of inerter and SAI in WEC, in Bubbar and Buckham (2018), inerter is used to implement optimal geometry control.…”

Section: Introductionmentioning

confidence: 99%

Application of semi-active inerter in a two-body point absorber via force tracking

Hua

Chen

et al. 2021

Transactions of the Institute of Measurement and Control

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In this paper, a self-reaction point absorber (PA) wave energy converter is studied, where wave energy is collected by the relative motion of the on-board plate and the buoy. The purpose of this study is to increase the relative displacement to obtain the maximum power. A semi-active inerter (SAI) is applied in the system, which is controlled by a force-tracking (FT) strategy. Two parts are required in the FT strategy: a target active control law; and a proper control law to adjust the inertance to track the active force (AF). The target control law is obtained by the full-state feedback of the state-space model of a two-body PA . The control law to adjust the inertance is to saturate the AF between the maximal and minimal semi-active force of an SAI. Both linear time-invariant system and linear time-varying system are studied. Power absorption is improved in both two systems by the application of SAIs. Moreover, the influence of dimensionless parameters on the ratio of power absorption improvement in the considered linear time-varying system is studied. Numerical simulation shows that the ratio of power absorption improvement is most sensitive to the changes of mass ratio of the on-board plate and the buoy.

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Enhanced power absorption of a point absorber wave energy converter using a tuned inertial mass

Cited by 35 publications

References 32 publications

Numerical evaluation of a two-body point absorber wave energy converter with a tuned inerter

Numerical evaluation of a two-body point absorber wave energy converter with a tuned inerter

Adaptive and Robust Operation with Active Fuzzy Harvester under Nonstationary and Random Disturbance Conditions

Application of semi-active inerter in a two-body point absorber via force tracking

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