Tri-stable behavior in mechanical oscillators to improve the performance of vibration energy harvesters

This paper reports a novel nonlinear oscillator for energy harvesting from wide-spectrum sources. The proposed solution improves previous studies (e.g. linear, bi-stable behaviors) focusing the attention on a tri-stable oscillator composed of three magnetically coupled PZT-beams. In order to provide repulsive forces the magnets have been equally oriented and disposed at 120°. This approach presents several intriguing characteristics such as: compact device, high performance in terms of resolution, suitable to be integrated, wide band of response. The system has been analytically modeled and an experimental prototype has been performed obtaining very intriguing results.