| Wave energy is a clean and abundant renewable energy source.According to statistics,if the waves in China's coastal areas can be used,it can provide half of China's electricity production.In coastal areas where China's economic development is very active,the demand for electric energy is very large,and coastal areas are the best location for developing wave energy.Therefore,it is of great significance to develop the wave energy in the coastal waters of China.The solo duck wave energy converter(WEC)has a high level of energy conversion efficiency and has a very broad application prospect.However,it also has the following problems: its commonly used hydraulic load has the disadvantages of large energy loss in the intermediate transmission process,high maintenance costs,and oil leakage;its energy conversion efficiency reduced significantly when the wave period deviates from the natural period of the device;the optimal layout of its array has not been fully studied.In view of the above problems,this paper proposes a direct-drive rotary generator as a load for the solo duck WEC,applying latching control to the solo duck WEC to increase the energy capture efficiency and studies the optimal layout of solo duck WEC arrays.In order to solve the problems of the hydraulic load in the traditional solo Duck WEC,the direct-driven rotary generator was proposed to be the load of the Duck WEC,the basic kinematics of the Duck WEC was established,the energy capture efficiency of direct-drive and hydraulic loads was compared,the problems of the Duck WEC was analyzed.The result shows that the direct-drive scheme can reduce the energy loss in the transmission process,reduce the maintenance cost and avoid the leakage of oil.The numerical analysis done by ANSYS AQWA software shows that when under both regular waves and irregular waves,the wave energy capture ability of direct-drive and hydraulic load is close to each other.When the wave period is close to the natural period of the Duck WEC,it has a high efficiency.However,when apart from the natural period,the efficiency decreases significantly.In order to solve the problem of declining energy capture efficiency when the wave period deviates from the natural period of the device for the Duck WEC,this paper studies the latching control problem,the latching control model was established,the optimal latching control strategy of the Duck WEC was obtained,the results show that: with the increase of the prediction time of the excitation force,the maximum relative capture width gradually increases,and the optimal load damping coefficient gradually decreases;when a certain number is exceeded,the maximum relative capture width and the optimal load damping factor will no longer change significantly.Applying the proposed latching control strategy,the maximum relative capture width can be increased by an average of 70% and the optimal load damping coefficient can be reduced by an average of 60%.The experimental system of solo Duck WEC was constructed,and the estimation method of the excitation force of the duck body in the intermittent motion state during the latching control process was proposed.The verification experiment was completed.The experimental results showed that: under the action of regular waves and irregular waves,the latching control can effectively improve the energy capture efficiency of the solo duck WEC and reduce the optimal load damping coefficient.When the wave period deviates from the natural period of the solo duck WEC,the experimental results are in good agreement with the numerical results.This verifies the accuracy of the numerical calculations in this paper.The layout scheme of solo duck WEC array with latching control is studied,and the main factors affecting the hydrodynamic interaction of each unit of the array under optimal energy capture conditions are analyzed.The kinematic model of the array in both the frequency and time domain are established,and the optimal layout of the solo duck WEC array in latching control condition is obtained. |
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