Single-Capacitor Electret Impact Microgenerator

Abstract

A new type of electrostatic microgenerator is presented that converts mechanical microvibrational energy into electric energy. The energy conversion mechanism is as follows. External microvibrations are transmitted to the device frame. The thin electret layer sputtered to the silicon substrate surface was fixed on the frame and the moving electrode was fixed by a weak suspension and comes into contact with the electret surface under the action of vibrations. A two-stage impact process is described: coming into contact with the spring stop that models the undulation of the contact surfaces, and direct impact on the electret surface. A numerical modeling of the generator operation is performed and analytic estimates of the generated power are obtained. It is shown that the energy generated by this motor is significantly higher than the energy generated by the classical mechanism based on the excitation of the forced vibrations of the moving plate. Experimental measurements of the microgenerator prototype parameters confirm the results of the theoretical modeling.