Rotary Capacitor Measurement Setup for Evaluating the Internal Biasing of Electrostatic Energy Harvesters

In this paper a rotary capacitor measurement setup for evaluating internal biasing (contact potential difference) of electrostatic energy harvesters is presented. The macroscopic rotary capacitor consists of two stators and a rotor which are based on standard PCB materials. An analytical model was developed by means of an equivalent electrical circuit and a time-dependent description of the geometrical behaviour of the rotary capacitor. Simulations were performed and refined by detailed FEM calculations. The rotary capacitor measurement setup was extensively characterized and compared to the model. Finally, first measurements of internal biasing of the rotary capacitor with different stator material combinations were done.