Characteristic Analysis Of Double Bi-stable Piezoelectric Vibration Energy Harvester And Research In Automobile

Nowadays,various miniature sensors are widely used.Most of these devices are used conventional batteries for power.However,conventional batteries are large in size and having a limited life span.In the meanwhile,some sensors have problems with battery replacement,such as tire pressure monitoring sensors in automotive tires.In order to obtain lasting and stable power supply,vibration-based piezoelectric energy harvesting has become a popular research direction.The bi-stable energy harvester(BEH)can convert the vibration energy in the environment into electric energy in a considerable wide range of low excitation frequency to realize energy recovery and utilization,and provide lasting and stable power supply for the sensors.Based on the BEH,this paper studies and designs a double bi-stable energy harvester(DBEH)to improve the vibration energy collection efficiency and system's power generation capacity.In this paper,the output response of BEH and DBEH has been deeply studied through theoretical modeling,numerical simulation and experimental verification.The main research contents are as follows.1.The research status of the piezoelectric vibration energy harvesting system are summarized and the related technologies have been studied.The amplitude threshold of the piezoelectric vibration energy harvesting system is analyzed and calculated.The selection of the energy storage components of the system and the selection of the rectifier circuit are analyzed.2.The magnetic potential energy expressions between two magnets and the magnetic repulsive energy model of the system are established.Then the lumped parameter model is established and the electromechanical equations of the DBEH system are calculated.Analyze the dynamic response and voltage output response of DBEH system with different excitation amplitudes,different excitation frequencies,different load resistances and different initial values under harmonic excitation.Comparing the results with BEH system,the results show that the DBEH system can more easily move between the wells across the barrier height,and the DBEH system has a higher voltage output,which can provide better power for the sensor.3.The filtered white noise is used to simulate the vibration input signal when the vehicle is running,this signal is used instead of the harmonic excitation,and then the output response of the DBEH system is analyzed.It is found that the output voltage of the system will increase with the increase of the noise intensity.At this time,it is similar to the response of the system under harmonic excitation,the system also has a optimally matched resistance,where the output power of the system is highest.4.In order to verify the correctness of the simulation results,BEH and DBEH were designed.The effect of different excitation on the system output was studied.The output of the DBEH system during the simulated vehicle running was studied.The experimental results are in accordance with the simulation conclusions,which prove that the DBEH system can collect and transform the vibration energy at wide range of low excitation frequency,and the energy conversion efficiency is higher than BEH system.The dissertation studies the DBEH system,studies the dynamics and voltage response of the system,and provides a viable solution for the collection and conversion of vibrational energy in the environment.It lays the foundation for further research.