Nonlinear Oscillations in a MEMS Energy Scavenger

The dynamics of an electret-based, capacitive, vibration-to-electric micro-converter (energy scavenger) is described by a set of ODEs where a second-order equation is coupled to two first-order equations through strongly-nonlinear terms. The nonlinear regimes of forced oscillations are analyzed with a semi-analytical approach, finding that the system exhibits features typical of Duffing-like nonlinear oscillators, such as jumps and multivalued frequency-response curves, with both stable and unstable periodic solutions. It is also proved that, for appropriate combinations of parameters, the system acts as a linear, damped oscillator, independently of the oscillation amplitude: in this case, the nonlinear coupling term reduces to a viscous-like term, physically interpretable as electromechanical damping.