Research Of Vibration Response Mechanism And Outputcharacteristic On Micro-Vibration Energy Harvester

With the rapid development of the wireless sensor network, embedded system, radio frequency identification, and various kinds of implantable MEMS sensors, the electronic products are more likely to be miniaturized, integrated, wireless and portable. However, the power supply problem has not been solved effectively. Conventional batteries, cable power and micro battery are greatly limited at the aspects of life, working conditions and cost, devoting more and more attention to the energy harvesting technology.Based on the diamagnetic levitation, a micro vibration energy harvester was studied in this paper. The structural model and work principle of the energy harvester was introduced, and the stability, magnetic force and diamagnetic force of the diamagnetic levitation were analyzed theoretically. The interpolation error of the finite element calculation was discovered during the simulation process of the magnetic and diamagnetic force in COMSOL Multiphysics. With the subtraction of calculated values under different material parameters, the simulation error was eliminated. A systematic and reliable structure design method of the energy harvester was obtained after the simulation calculation of its overall structure size, and the validity of this method was verified by the experiment. The balance distance and levitation space of the floating magnet with different structural forms were further analyzed, which provided guidance for the structure optimization of the energy harvester from the perspective of static levitation characteristics.Secondly, theoretical analysis and simulated calculation of the vibration response for the energy harvester under external vibration source excitation were carried out from the vertical and horizontal direction. The natural frequency of the floating magnet for linear and nonlinear vibration was calculated. The forced vibration of the floating magnet along the vertical and horizontal direction was simulated in Simulink, and the nonlinear vibration response curve was obtained. Since the energy harvester was likely to be installed on the inclined surface, the whole tilt state and vibration response of the energy harvester were analyzed and discussed.Then the induced voltage of the energy harvester was analyzed and calculated based on the theory and simulation. According to the distribution of the magnetic field around the floating magnet, the layout scheme of the copper coils is determined. With the theoretical analysis of the induced voltage and output power, the influence factors of the induced voltage was obtained. The induced voltage was simulated in the finite element analysis software COMSOL Multiphysics, and the effect of external excitation amplitude, frequency, structure type of the floating magnet and the copper coil parameters on the induced voltage was investigated in the software.Finally, the experimental platform of the energy harvester was set up. Under the external vibration source, the induced voltage of the energy harvesting device was tested. Comparing the simulation value with the experiment value, the error source of the differences and the improving measures of the experimental platform were presented.