A bidirectional vibration powered electric energy generator based on electrostatic transduction using In-Plane Overlap Plate (IPOP) mechanism

In this paper, the design, fabrication and initial characterization results of a bidirectional, vibration powered, bulk silicon-based electric energy generator are addressed. The converter is based on an In-Plane Overlap Plate (IPOP) configuration. Its mechanical design is inspired from 2D gyroscope. In most of real systems, the axis of the external vibrations is not known and if we assume that the available energy is equally distributed over the three degrees of freedom, the ldquo2Drdquo-transducer is potentially twice more efficient than its one-degree of freedom counterparts. The maximum theoretical power convertible from the mechanical to electrical domain is predicted using the mechanical resonance frequency characterization along with FEM simulations based capacitance variation. With 6 V pre-charge voltage the maximum theoretical power converted is 2.6 muW at a 246 Hz vibration frequency from a 10 times 10 times 0.9 mm³ transducer.