Design of a micropower generator

Abstract

In some implanted and distributed system, the power consume of these devices is tiny (generally just at uW level), and effective, long term, power supplier are lacking. For this need, several forms of vibration-driven MEMS micro generator are possible and are reported in the literature, with potential application areas including distributed sensing and ubiquitous. Our goal is to develop a micro power source translating the ambient vibration energy into the electric power which can offer 30uW power to some sensors. In our work, we designed the power generator based on a charge induced by a electret transported between two parallel capacitors. It consists of combed in-plane capacitor, electret and selenium rectifier. The combed in-plane capacitor is the key part of the generator; it will fulfill the charge transportation and translation of the energy. We design the structure of the capacitor and simulate the amplitude-frequency characteristic and phase-frequency characteristic. And then the electric-mechanic coupling is simulated, and we know the relationship between output voltage, power density and frequency. Finally a micro power generator is designed and its dimension is 8000*3000um.When the exterior oscillation is 10um and the load is 1e-6ohm, the output power is 30uW and the voltage is 4.1V.