Energy Harvesting Enhancement by Vibrational Resonance

The idea to use environmental energy to power electronic portable devices is becoming very popular in recent years. In fact, the possibility of not relying only on batteries can provide devices longer operating periods in a fully sustainable way. Vibrational kinetic energy is a reliable and widespread environmental energy, that makes it a suitable energy source to exploit. In this paper, we study the electrical response of a bistable system, by using a double-well Duffing oscillator, connected to a circuit through piezoceramic elements and driven by both a low (LF) and a high frequency (HF) forcing, where the HF forcing is the environmental vibration, while the LF is controlled by us. The response amplitude at low-frequency increases, reaches a maximum and then decreases for a certain range of HF forcing. This phenomenon is called vibrational resonance. Finally, we demonstrate that by enhancing the oscillations we can harvest more electric energy. It is important to take into account that by doing so with a forcing induced by us, the amplification effect is highly controllable and easily reproducible.