Control Strategy for a Point-Absorber Wave Energy Converter

2019 ◽  
Author(s):  
Qiao Li ◽  
Motohiko Murai
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Control Strategy ◽  
Wave Energy Converter ◽  
Total Power ◽  
Control Force ◽  
Energy Converter ◽  
Natural Period ◽  
Wave Condition ◽  
Electric Generator

Abstract Linear driving wave energy converter (WEC) system need to control the electric generator to obtain more power generation. Electric power is consumed by control, but it is possible to control the natural period of the floating motion. By resonating the movement of the float part with wave, it is possible to obtain the power generation more than the control power consumption, the total power generation performance will be improved. In this study, to ensure the WEC safety and performance for various wave condition, especially high wave height, the electrical control algorithms are changed for different wave condition. A control strategy is proposed for various wave condition considering the control force limitation and motion amplitude limitation. Basis on the control strategy, the range of operation by electric control is estimated. In addition, by estimating the expected value of power generation in the set sea, the setting parameters of the WEC can be discussed according to the wave situation.

scholarly journals A Piezoelectric Wave-Energy Converter Equipped with a Geared-Linkage-Based Frequency Up-Conversion Mechanism

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 204
Author(s):  
Shao-En Chen ◽  
Ray-Yeng Yang ◽  
Guang-Kai Wu ◽  
Chia-Che Wu
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Wave Motion ◽  
Wave Energy Converter ◽  
Gear Train ◽  
Piezoelectric Composite ◽  
Maximum Height ◽  
Resistive Load ◽  
Linkage Mechanism ◽  
Energy Converter

In this paper, a piezoelectric wave-energy converter (PWEC), consisting of a buoy, a frequency up-conversion mechanism, and a piezoelectric power-generator component, is developed. The frequency up-conversion mechanism consists of a gear train and geared-linkage mechanism, which converted lower frequencies of wave motion into higher frequencies of mechanical motion. The slider had a six-period displacement compared to the wave motion and was used to excite the piezoelectric power-generation component. Therefore, the operating frequency of the piezoelectric power-generation component was six times the frequency of the wave motion. The developed, flexible piezoelectric composite films of the generator component were used to generate electrical voltage. The piezoelectric film was composed of a copper/nickel foil as the substrate, lead–zirconium–titanium (PZT) material as the piezoelectric layer, and silver material as an upper-electrode layer. The sol-gel process was used to fabricate the PZT layer. The developed PWEC was tested in the wave flume at the Tainan Hydraulics Laboratory, Taiwan (THL). The maximum height and the minimum period were set to 100 mm and 1 s, respectively. The maximum voltage of the measured value was 2.8 V. The root-mean-square (RMS) voltage was 824 mV, which was measured through connection to an external 495 kΩ resistive load. The average electric power was 1.37 μW.

scholarly journals Multi-Mode Wave Energy Converter Design Optimisation Using an Improved Moth Flame Optimisation Algorithm

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3737
Author(s):  
Mehdi Neshat ◽  
Nataliia Sergiienko ◽  
Seyedali Mirjalili ◽  
Meysam Majidi Nezhad ◽  
Giuseppe Piras ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Total Power ◽  
Energy Converter ◽  
Wave Regime ◽  
Optimisation Algorithm ◽  
Wide Range ◽  
Evolutionary Optimisation ◽  
Optimisation Methods ◽  
Optimisation Algorithms

Ocean renewable wave power is one of the more encouraging inexhaustible energy sources, with the potential to be exploited for nearly 337 GW worldwide. However, compared with other sources of renewables, wave energy technologies have not been fully developed, and the produced energy price is not as competitive as that of wind or solar renewable technologies. In order to commercialise ocean wave technologies, a wide range of optimisation methodologies have been proposed in the last decade. However, evaluations and comparisons of the performance of state-of-the-art bio-inspired optimisation algorithms have not been contemplated for wave energy converters’ optimisation. In this work, we conduct a comprehensive investigation, evaluation and comparison of the optimisation of the geometry, tether angles and power take-off (PTO) settings of a wave energy converter (WEC) using bio-inspired swarm-evolutionary optimisation algorithms based on a sample wave regime at a site in the Mediterranean Sea, in the west of Sicily, Italy. An improved version of a recent optimisation algorithm, called the Moth–Flame Optimiser (MFO), is also proposed for this application area. The results demonstrated that the proposed MFO can outperform other optimisation methods in maximising the total power harnessed from a WEC.

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