Research And Application Of Wide-Band Vibration Energy Acquisition Device For Wireless Sensor Nodes

With the high-speed innovation of low-power electronic equipment technology,the requirement of wireless sensor technology in mechanical production process has also been greatly promoted.At present,battery power supply is still the power supply mode of some wireless sensor nodes.As a chemical product,the existence and consumption of batteries greatly increase the potential pollution of the environment,as well as the huge consumption of economic and human costs,which makes the sensor difficult to work in the process.Therefore,the research of self-power supply technology based on environmental energy acquisition has attracted much attention.Wave energy is a kind of abundant energy,but it is also easy to be wasted.Because of the low frequency of waves,the collection of energy sources is greatly hindered.Piezoelectric vibration energy collection device is an effective energy absorption and conversion device in low frequency environment.When the ambient excitation frequency equals the self-frequency of piezoelectric cantilever beam,the beam resonates,and the amplitude and output voltage reach the maximum.At present,the conversion efficiency of single structure vibration energy acquisition device is low,and the vibration source is unstable in the environment.The single cantilever beam is very sensitive to the vibration frequency response.It is not easy to achieve a good match between the environmental vibration source and the resonance frequency of the acquisition structure,resulting in energy waste.Therefore,a broadband vibration energy acquisition system based on piezoelectric ceramics is proposed and optimized as a wave energy acquisition system.Through finite element analysis,the relationship between the size of the beam and the natural frequency is obtained,and the structure of the piezoelectric cantilever beam is optimized by combining the theoretical formula.Finally,whether the natural frequency of the piezoelectric cantilever beam is within the design target range is studied experimentally,and the bearing capacity of the piezoelectric cantilever beam is measured.An application of self-energy supply device for wireless sensor network nodes for buoys is designed.Firstly,AUTOCAD is used to draw the graphical structure to optimize the shape and energy capture of the floating body,and the depth of the floating body entering the water to capture the wave.Thirdly,the amplitude-frequency characteristic experiment and power test are carried out to obtain the natural frequency,amplitude-frequency characteristic curve and load characteristic curve of the energy conversion system.In this paper,the energy collection efficiency of a single cantilever beam is compared with that of a broadband one.Based on the single cantilever beam,a broadband energy collector for wave vibration frequency in ocean environment is proposed.The research data show that the wide-band multi-mode vibration energy acquisition structure can widen the energy capture range of the collection device.Through comparative experiments,the piezoelectric oscillators with maximum length of 56 mm,50mm,48 mm,42mm,width of 20 mm,18mm,15 mm,12mm,maximum thickness of substrate of 0.25 mm,thickness of piezoelectric sheet of 0.2mm and mass of 3.57 g,7.73 g,12.04 g and 18.79 g are selected.Enough to provide the required energy for the electronic equipment in the buoy.