Study On Widening Frequency Band Mechanism And Key Technology Of Micro Electromagnetic Vibration Energy Harvester

With the rapid development of wireless mobile electronic devices and systems, the micro energy harvesters based on MEMS technology, which harvests energy from environment, has become a research hotspot in recent years. Micro energy harvesters which harvest energy from the environment and convert it into electricity have many advantages such as smaller volume, simple structure, long service life, green environmental protection and low cost. They are ideal power for low-power micro devices and system and have become one of the research hot-spot in the micro energy technology. But there are some prombles not solved in pratical application of micro energy harvesters. In order to improve the micro vibration energy harvester adaptability to the environment, the frequency band widening mechanism and key the technology of micro electromagnetic vibration energy harvesters were studied in this thesis. It has an important scientific significance and specific application requirements.In this thesis, aimed at widening the bandwidth of the micro electromagnetic vibration energy harvester, a new electromagnetic vibration energy harvester with multi-modals and nonlinearity vibration-picking structures is proposed. Corresponding dynamics models was established. Based on the dynamics model, the working principle and frequency band widening mechanism were carefully analyzed. According to the characteristics of the specific application environment and the theory of demand, determine the technical parameters of micro electromagnetic vibration energy harvester. A new optimization method of structure parameters was proposed by calculation transduction factor of the rectangular permanent magnet. The structural parameters were optimized in order to make the micro electromagnetic vibration energy harvester have a broadband and the maximum power output at the same time. The ANSYS simulation combined with Duffering equation to analyze the effect of nonlinearity on the frequency bandwidth. Prototype of the electromagnetic vibration energy harvester was manufactured. The total volme of prototype is 5.625cm3. Set up the experimental platform. The principle prototype was tested and the measurement results were analyzed.The mainly research works in this thesis are:(1) The frequency widening techonolgy of micro electromagnetic micro energy harvesters at home and abroad was studied. In order to solve the problem which working bandwidth narrow of the electromagnetic energy harvester, the paper research goal and content were determined.(2) In order to widening the bandwidth, a micro electromagnetic vibration energy harvester with multi-modal and nonlinear technology was proposed. The dynamics model was established. Based on the dynamics model, the vibration characteristics, the magnetic properties and frequency widening mechanism of the electromagnetic vibration energy harvester were analyzed.(3) According to the specific vibration environment, a new optimizing method for structure parameters of the micro electromagnetic energy harvester was proposed. Structure parameters were determined and optimized. The ANSYS simulation combined with Duffering equation to analyze the effect of nonlinearity on the frequency bandwidth.(4) According to structure of the proposed micro electromagnetic vibration energy harvester, the corresponding processes were determined. The principle prototype was processed and assembled.(5) To test the output performance of the principle prototype, the experimental platform was set up. The test results shows: The prototype meets the design requirement and is able to extend bandwidth effectively in low-frequency vibration environments. When the acceleration is greater than 1g, the prototype can extend frequency effectively at the first order and second resonance frequency, there was no significant change in the bandwidth at the third order resonance frequency. At 1.5g excitation acceleration and the frequency of 45.6 Hz, the maximum bandwidth of the prototype is 10.1 Hz, corresponding load-voltage and output-power are 336 mV and 112.9 μW repectively. The test results are coinciding with theoretical analysis.