Piezoelectric-based broadband bistable vibration energy harvester and SCE/SSHI-based high-power extraction

This paper presents ambient mechanical vibrations as an alternative source for energy harvesting, especially beneficial where alternatives such as light, wind, biomass and thermal energy are limited, e.g., powering underground sensors. Transduction of ambient kinetic energy, e.g., the vibrations from thunder and field work, into electrical energy using piezoelectric generators has been investigated, utilizing a nonlinear bistable broadband piezoelectric harvester. A new model for the bistable piezoelectric harvester is suggested based on the standard Butterworth van Dyke model and its validity demonstrated through simulations. For efficient extraction of the transduced energy, we employ synchronous charge extraction (SCE) and parallel synchronized switch harvesting on inductor (SSHI). The switching in these circuits is implemented using a fully self-propelled, low-power electronic breaker circuit, capable of detecting extrema in the input to perform switching. The power outputs from simulation of the bistable harvester have been presented, with the SCE and parallel SSHI providing respective average outputs of 78.5μW and 125μW for a sinusoidal input of 0.326N at 10Hz applied to a 69.1 × 16.8 × 0.64 mm³ cantilever (piezoelectric dimensions 35.56 × 14.48 × 0.2 mm³). This shows significant gains over the harvested power reported in literature.