Optimization design and experimental test of an electret-based electrostatic energy harvester
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摘要: 針對環境中的低頻振動能量,建立了一種雙端固支梁振動式駐極體靜電俘能器理論模型.利用Matlab/Simulink數值仿真對靜電俘能器的各項關鍵參數進行了優化.分別研究了靜電俘能器的輸出功率、諧振頻率、半功率帶寬與駐極體表面電位、空氣間隙以及負載電阻的關系.在研究中,外部激勵加速度幅值及駐極體尺寸保持恒定.數值分析結果如下:(1)存在一個最佳表面電位使得靜電俘能器的輸出功率達到最大值,隨著表面電位的增加,軟彈簧效應逐漸增強使得俘能器諧振頻率發生偏移,半功率帶寬逐漸增大.(2)當表面電位一定時,存在一個最佳初始空氣間隙使得功率達到最大,隨著間隙的增大,半功率帶寬隨之減小.(3)當表面電位和空氣間隙保持一定時,存在一個最佳負載使得功率達到最大,隨著負載的減小,諧振頻率發生偏移.(4)當空氣間隙一定時,存在一個最佳負載使得帶寬達到最大,且表面電位越大,相同負載下的帶寬越大.實驗測試了不同負載電阻下俘能器的輸出特性:輸出功率及半功率帶寬都隨著負載電阻的增大,先增大而后減小.當負載電阻為90MΩ時,對應的最大輸出功率為0.188 mW;當負載電阻為330 MΩ時,對應的半功率帶寬達到最大值為4.7 Hz.Abstract: A theoretical model of a vibrating electret electrostatic energy harvester for a double-ended fixed beam was established herein for a low-frequency vibration energy in the environment. The key parameters of the electrostatic energy harvester were optimized by a MATLAB/Simulink numerical analysis. The relationship between the output power, resonant frequency, and half-power bandwidth and the electret surface potential, air gap, and load resistance was also studied. The magnitude of the external excitation acceleration and the size of the electret remained constant. The numerical results are as follows:(1) the existence of an optimal surface potential makes the output power of the electrostatic energy harvester reach the maximum value. The soft spring effect gradually increases with the increase of the surface potential, making the resonant frequency of the energy harvester device shift. The bandwidth also gradually increases. (2) An optimal initial air gap maximizes the power when the surface potential is constant. The half-power bandwidth decreases as the gap increases. (3) An optimal load maximizes the power when the surface potential and the air gap remains constant. The resonant frequency is offset as the load decreases. (4) An optimal load is used to maximize the half-power bandwidth when the air gap is constant. The larger the surface potential, the greater the half-power bandwidth under the same load. Experiments show that the output characteristics of the energy harvester under different load resistances have the following characteristics:with the increase of the load resistance, the output power and the half-power bandwidth increase at the beginning, then decrease. The maximum output power is 0.188 mW when the load resistance is 90 MΩ. In addition, the half-power bandwidth reaches the maximum value of 4.7 Hz when the load resistance is 330 MΩ.
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Key words:
- electret /
- surface potential /
- air gap /
- load resistance /
- resonance frequency /
- frequency band width /
- experiment test
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參考文獻
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