A MEMS Magnetic-Based Vibration Energy Harvester

This paper presents the design, analysis and integrated fabrication of a MEMS magnetic-based vibration energy harvester targeted for machine health monitoring. The design consists of Si-springs, permanent magnets as mass, and coils wound on the top and bottom side of the harvester package for mechanical-to-electrical energy conversion based on the Lorentz-force principle. The harvester is optimized to have its translational resonant-mode match external vibrations while separating higher-order modes. Mechanical and magnetic optimization of the harvester is carried out together with optimization of its power and control electronics in order to provide maximum output power from a vibration input that can vary its frequency by +/- 5%. The harvester achieves an open-circuit voltage amplitude of 145 mV and delivers 165 mu W to a matched load at the resonance frequency of 45.7 Hz.