A wideband vibration energy harvester with integrated energy management designed for harsh environment.

Inhalt:
Bistable energy harvesters (BEH) are well adapted devices to deal with the variation of the vibration source frequency spectrum. Indeed, the non-linear motion of this kind of harvester allow to reach a harvesting bandwidth up to 50% of the resonant frequency compared to 1-2% of the resonant frequency typically for conventional linear energy harvesters. CEDRAT TECHNOLOGIES proposes a design using buckled beam and Amplified Piezoelectric Actuator (APA(r)) technology based on an architecture patented by the USMB. The nonlinear behavior of such a kind of energy harvester has already been studied in the literature and has demonstrated promising results. Due to the use of buckled beam, the bistable energy harvester is very sensitive to the thermal expansion resulting from the harsh environment. In this paper, it is proposed an improved design to manage the thermal expansion and ensure harvesting capabilities on a wide temperature range from -40deg C to +80 °C. Furthermore, an electronic extraction circuit has been implemented to deliver a regulated output voltage to power an IoT. Moreover, this electronic circuit can deal with spontaneous excess of energy by storing it into a supercapacitor or a battery and sink this energy to still powering the IoT when the vibration level decrease. The BEH with the electronic extraction circuit can generate a power of 8mW. The combination of an athermalized Bistable Energy Harvester with an electronic extraction circuit increases the technological readiness level to be integrated in system subjected to harsh environment like railway application for instance.