Development of a Metal-Cantilever Electrostatic Vibration Power Generator Combined With Potassium Ion Electret Technique

We have developed a metal-cantilever electrostatic vibration power generator that has comb-drive electrodes made of a SOI wafer at the tip of the cantilever. The comb-drive electrodes in which built-in electric field is given by potassium ion electret technique acts as an energy transducer from mechanical vibration power to electrical one. The metal cantilever part is formed separately, and assembled with the comb-electrodes on a bakelite plastic. This device showed strong nonlinear frequency responses, in which spring hardening was observed when applied acceleration was small while spring softening when high acceleration. About 30μW output power was observed at 0.03G_RMS acceleration, and the maximum 90% conversion efficiency achieved at 0.01G_RMS acceleration.