Research On Buoy-Rope-Drum Wave Power System

At this stage, development of green and renewable energy has become the consensus of the international community. Many countries are stepping up the pace of development of green and renewable energy. Conuties all over the world pay attention to the decelopment and utilization of wave energy, whose actual exploitation quantity is the highest, and various forms of wave power generation device have been developed. In this paper, buoy-rope-drum wave energy generation device is researched, which is simple, low cost, high wave energy conversion rate and good adaptability.Summarizing domestic and foreign oscillating buoy wave power device experience in development, and combining independent innovative, motion response, damping ratio and mooring system of buoy-rope-drum wave power device are studied deeply. Theoretical analyses, numerical calculation, numerical simulation, model test and prototype sea trial are used in the process of analysis. According to the basic theory of wave theory and its applicability, stokes wave theory is suitable for this case. The overall design scheme and working principle of buoy-rope-drum wave energy generation device is briefly described.Base on wave theory, motion model of buoy is established in ideal and actual state. Motion law of 11 buoys with same bottom diameter and different quality is got. The application program -- BuoyRopeDrumGS2014 is developed to size up wave theory and calculate motion response of buoy. Results show that resonance phenomenon in the ideal state is true and it is consistent with related scholars. But, it is found that resonance phenomenon is unfulfillable because of the length of buoy, which is not always in the water. This is to say the motion system is not consecutive, and the resonance phenomenon is unable to realize.On the basis of motion response of free buoy, the law of buoy with loading and optimal damping is studied in frequency domain and time domain. Using the support movement caused by the forced vibration theory, the motion model of buoy is established and analyzed in the complex frequency response to get amplitude frequency characteristic and phase frequency characteristic curve. Power formula is derived according to the vibration theory. In time domain, piecewise function is used to establish the motion model because of different forces in rising and falling stages. Laws of motion of buoy with damping and relationship between power and damping coefficient are got using BuoyRopeDrumGS2014. Finally, results of frequency domain and time domain are carried out to verify the method using the numerical simulation analysis.Motion model of buoy with single mooring is established based on environmental loading and catenary equations to analysis horizontal positioning performance of mooring system. According to the result of single mooring system, hydrodynamic performance of three mooring system is calculated. Results show that three mooring system could limit motion of buoy in horizontal and rotating around Z axis. Mooring system could provide a stable base for generation system.Experimental tank, wave device, wave device and power generation system are developed base on similitude theory of shape, motion and dynamic.24 groups of experiments are taken with 8 frequencies and 3 wave height. Results show that there is resonance phenomenon, which results in system instability. For the power generation performance,4 groups experiments are taken with 2 wave periods and 4 buoy weight, whose results show power curves of the load resistance first increase and then decrease. Resonance can enhance the amplitude and power generation system, which lead to big swings and impact.Physical prototype is designed and manufactured based on theoretical calculation, numerical simulation and model experiment, which is put in designated sea area. Electrical controlling and monitoring part monitor and control the generation device almost in real time. Generator performance parameters and real time image signal are transferred back to the monitoring room by wireless. By analyzing test data on the sea, it is shown results of theoretical analysis and model experiments are almost consistent, which proves the analysis is correct.