Research And Application Of Wireless Sensor Node Self Generation System Based On Vibration Energy Collection

This paper proposes a piezo-vibration energy harvester structure with a cantilever beam and an additional mass plug-in connection.This plug-in connection structure not only guarantees that the center of gravity of the additional mass at the end is collinear with the center of gravity of the beam,but also can effectively prevent the cantilever The compressive fracture of the piezoelectric layer caused by the transverse vibration of the beam with a large displacement;Based on this piezo-electric cantilever beam structure with the plug-in connection,the Euler-Bernoulli beam theory and the Rayleigh beam theory are derived.The electromechanical coupling dynamics differential equations of piezoelectric cantilever beams are used to regularize the electromechanical coupling differential equations by using the orthogonality of the cantilever beam natural modes.The regularity of piezoelectric cantilever beams under the condition of R-AC load circuit is analyzed and studied.The relationship between the normalized excitation frequency,the regularized load resistance,the displacement,the regularized voltage,the regularized current and the regularized power response.A finite element simulation model of plug-in connected bi-piezoelectric vibration energy collectors was established using the finite element analysis software ANSYS14.0.The vibration modes of piezoelectric cantilever beams were extracted and the vibration modes under different vibration modes were compared and analyzed.The distribution of stress and strain inside the electrical cantilever beam leads to the conclusion that the low-order modes are more suitable for piezoelectric energy conversion.The experimental aspects of the piezoelectric cantilever energy collection process were analyzed.First,built a vibratory piezoelectric energy collection system test bench;Second,the experimental scheme of piezoelectric vibration energy collection system under the condition of R-AC load circuit was designed to study the influence of various parameters in vibration environment and circuit load on thepower conversion and output;Thirdly,the theoretical model of energy prediction of piezoelectric vibration energy collector based on Euler-Bernoulli and Rayleigh beam theory is compared and analyzed.The analysis results show that the Euler beam theory overestimates the modal displacement of the piezoelectric cantilever beam and causes the theoretical output of the piezoelectric cantilever beam energy prediction model to deviate from its actual value.Relatively speaking,only the bending vibration is considered.Rayleigh beam theory can reflect the real power output of piezoelectric cantilever beam more realistically.A self-powered wireless temperature monitoring node consisting of a piezoelectric vibration energy harvester,a power conditioning circuit,a temperature sensor,and a wireless transceiver was designed;a power conditioning circuit was designed and experimentally analyzed to provide wireless power through this power conditioning circuit.When the temperature monitoring node supplies power,the difference between the monitoring and sending process of the wireless temperature signal and the power supply voltage in the time history.