Design And Research On A Point-absorbing Wave Energy Power Generator In Sea-crossing Bridges

To ensure the normal operation and safety,the monitoring system in sea-crossing bridges widely uses a variety of sensors,monitoring equipments and other kinds of applications.However,the applications generally use a large number of batteries with limited capacity,which makes it difficult to fully satisfy the power demand for long-term monitoring.Wave energy,as a hot research object for environmental resources development,can be applied to the wide range of low-power applications in sea-crossing bridges.In this case,the near-zero energy consumption environment based on energy conversion can be applied to the bridge monitoring system in sea-crossing bridges of coastal areas and other kinds of low-power applications in sea-crossing bridges.By collecting free renewable wave energy from the ocean and converting it into electricity,we can reduce the use of batteries,realize permanent energy use and environmental protection,and promote near-zero energy conversion of sea-crossing bridges.Firstly,a point-absorbing wave energy power generator using zero-pressure-angle mechanism,double unidirectional bearings and flywheel to convert energy was proposed.The modular design idea is adopted to divide the structure of the wave energy power generator into four modules: wave energy capture module,power take-off(PTO)module,generator module and energy storage module.Secondly,in order to simulate the freewheeling motion process of the PTO due to the flywheel inertia,this paper combines the non-constant transmission ratio of the internal mechanism of the device to accurately study the kinematic and dynamical response,and establishes the mathematical model of dynamics theory and the power generation characteristics,carrying out sinusoidal input simulation and hydrodynamic parameters calculation by MATLAB program and ANSYS AQWA simulation environment,including the damping coefficients and the demonstrated power characteristics of the system under two cases of complete disengagement and engagement.Thirdly,the principle prototype of the point-absorbing wave power generator was made,along with testing and performance comparison of prototypes at different frequencies,damping and equivalent masses using servo-hydraulic mechanical test and sensing system(MTS).The experimental results and simulation findings were further combined to verify the accuracy of the theoretical model in performance prediction.The results show that the demonstrated power characteristics and generation performance of the prototype are in accordance with the theory and simulation,while the prototype performs as expected,with a mechanical efficiency of up to 81.87% and an output power of up to 5.49 W.Finally,combined with the application scenario of the point-absorbing wave power generator,the supercapacitor charging tests and field random wave tests were conducted to verify the feasibility of the device in harvesting wave energy and generating electricity,so as to provide fundamental research for applying the wave energy power generator to low-power applications in sea-crossing bridges.