Power MEMS—A capacitive vibration-to-electrical energy converter with built-in voltage

This paper reports on the design and analysis of a capacitive vibration-to-electrical energy converter. A theoretical design model of a parallel-plate electrostatic spring-mass-system is presented, based on state space equations. The charging of the parallel-plate capacitor takes place by utilizing materials with different work functions for the electrodes. Numerical simulations are performed in order to optimize design parameters targeting a maximum output power. The shown Micro-Electro-Mechanical System (MEMS) based capacitive energy converter is able to provide an output power of 4.28 μW at an external vibration with a frequency of 1 kHz and an amplitude of 1.96 m/s2 (0.2 g). A basic electronic circuit for storing the electrical energy is also introduced. Furthermore, a MEMS design and a process flow are presented.