Frequency Combs: A New Mechanism for MEMS Vibration Energy Harvesters

This paper presents a new mechanism of vibration energy harvesting via the generation of frequency combs due to nonlinear modal interactions. A frequency comb is characterized by multiple discrete spectral lines resulting from a single excitation frequency. This work demonstrates that frequency combs can be stimulated through internal resonance under unidirectional mechanical vibration. Further, harvesting via frequency combs shows good responsivity to wideband input excitation over 100 Hz, as a series of spectral lines enhances the overall response. For a membrane type MEMS piezoelectric energy harvester, the comb state covers 471-542Hz frequency range. A maximal root mean square voltage of 0.54V is achieved @485±50Hz (100Hz bandwidth), which is a factor of 3.6 as much as that achieved @485Hz single frequency excitation at the same excitation level.