A generator with nonlinear spring oscillator to provide vibrations of multi-frequency

A piezoelectric generator with nonlinear spring oscillator is proposed to provide multiple resonant modes for operation and improve conversion efficiency. In order to scavenge the vibration energy of multiple frequencies from a certain vibration source, two types of nonlinear springs have been employed and tested. The maximum output power of 5, 17.83, and 23.39 mu W for the nonlinear spring of 8.3 N/m with 1 g acceleration has been obtained under the resonant frequency of 89, 104, and 130 Hz, respectively. Its total output power of 46.22 mu W is obviously larger than the one of 28.35 mu W for traditional second-order spring-mass linear system. (C) 2011 American Institute of Physics. [doi:10.1063/1.3664223]