A Tri-Plate Variable Capacitor for Electrostatic Energy Harvesting Available to Purchase

Electrostatic power generators employ micro-fabricated variable gap capacitors to harvest mechanical vibration energy and have applications in wireless sensors networks [1]. This paper investigates a new tri-plate architecture for an in-plane, gap-closing, electrostatic micro-generator. Unlike double-plate designs, which rely on a half sweep movement of the movable electrode from a relative extreme displacement to a central position [1], the tri-plate design allows a full sweep of the movable electrode from opposite relative displacement extremes. This results in a significantly larger capacitance ratio that can increase power output by 40% over a comparable double plate design. Dynamic simulations in Simulink are used to determine the displacement of the movable electrode in order to verify design practicality and calculate power output.