Broadband energy harvesting using a nonlinear 2DOF MEMS electret power generator

This paper presents the modeling and experimental results of a novel nonlinear 2-degree-of-freedom (2DOF) MEMS electret power generator for broadband energy harvesting. The proposed 2DOF resonant system that comprises a primary and an accessory mass is constructed on a silicon wafer by double-side DRIE process. Two close resonances with frequency ratio of only 1.24 (590 Hz and 731 Hz) and comparable magnitudes are achieved for the first time for a 2DOF MEMS device. With further increasing the excitation, hardening nonlinearity induced by end-stop effect is engaged, resulting in resonant frequency drift upwards and further bandwidth convergence. The outcome of the work offers a promising wideband approach by combined advantages of both multi-modal and nonlinear mechanisms.