Electromagnetic transducer with bistable-RMSHI for energy harvesting from very weak kinetic sources

The low output voltage of energy harvester from ambient sources, such electrodynamic converters, makes the storage and use of energy in wireless sensors challenging. In this paper we propose an electromagnetic energy converter together with a novel energy management concept based on a nonlinear (Bistable) Random Mechanical Switching Harvesting on Inductor (RMSHI). The electromagnetic converter consists of a moving coil attached to a mechanical spring. It is able to harvest energy even from very weak vibrations close to 9 m/s
²
of applied acceleration. In particular the conceived structure works also in presence of random and voltage amplitude generated from the electromagnetic harvester less than bridge rectifier threshold (~1.4 V). We have already demonstrated the capability of the RMSHI in order to work as “unsynchronized” approach able to collect energy by using linear transducers (i.e. PZT oscillators, AlN Bridges, etc.). Here we propose a bistable-RMSHI with an electromagnetic harvester to improve its performance in presence of random kinetic sources. The system has been studied, realized and characterized, demonstrating the validity of our approach.