| In recent years,wireless sensors have been widely used in Marine monitoring platforms.How to improve the endurance and achieve long-term stable power supply is an urgent problem to be solved.Due to the complex and changeable ocean environment,once the common battery in the high salt and humidity environment is damaged,it cannot be replaced in time,which will affect the performance of the whole sensor network.So people are starting to develop wave energy harvesting devices that use local materials to power wireless sensors.With its advantages of small size,simple structure and low cost,wave energy piezoelectric power generation technology has become an ideal way to realize the power supply of small offshore monitoring platform.However,it is difficult for piezoelectric materials with high natural frequency to achieve efficient energy output due to the extremely low wave frequency.Therefore,this paper proposes a kind of built-in coupled pendulum wave energy piezoelectric harvester with the ability of secondary frequency increment.The research work of this paper mainly includes the following aspects:(1)Literature research.The research status of energy supply technology for small Marine equipment,wave energy conversion device and micro wave energy piezoelectric power generation device are analyzed.The advantages and disadvantages of two wave energy absorption schemes of double floating type and built-in pendulum type are summarized.The main research purpose and significance of this paper are discussed.(2)The structural design of the device.Combined with the advantages and disadvantages of the existing devices,a piezoelectric power generation device with built-in coupled pendulum is proposed,which can collect ocean wave energy and has the ability of secondary frequency increase.The 3D modeling of the device is completed by using Solidwork software,and the working principle of the device is introduced.(3)Theoretical derivation.Physical modeling and theoretical analysis of the device were carried out to get the expression of the horizontal wave force on the floating body,and the expression of the open-circuit voltage and average power generated by the vibration of the piezoelectric twin-crystal beam under external excitation.It is determined that the pendulum length,pendulum weight,floating mass and spring stiffness are the key factors affecting the energy conversion efficiency of the coupled pendulum system.(4)Structural simulation analysis,The mechanical and electrical system of coupling pendulum wave power generation unit is simulated and analyzed.Firstly,a virtual prototype model was established based on ADAMS environment,and then the simulation analysis was carried out on the device.The influences of floating body mass,internal pendulum length,pendulum weight,pendulum weight,spring stiffness and initial length of spring on wave energy absorption were respectively explored.(5)Experimental research.the production of the test prototype is completed,the experimental platform is designed and built.Through the crank slider mechanism to simulate the motion mode of the transducer,the piezoelectric plate performance tests are carried out,including the optimal load test and the end magnet test.The experiments of magnetic impact type piezoelectric generator are carried out,including single magnet excitation,double magnet excitation,double piezoelectric array and four horizontal piezoelectric array.The terminal response,open-circuit voltage and average power of a single piezoelectric plate are compared under four different excitation modes.The research in this paper provides a new idea for the long-term endurance of the small Marine monitoring platform. |
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