A high effectiveness impact-optimized piezoelectric energy harvesting interface system

This paper presents a novel high-performance impact-optimized interface system for an impact-driven piezoelectric energy harvester (PEH) which utilizes two independent parallel harvesting plans, that is, low-efficiency self-powered passive path and high-efficiency active maximum power point tracking (MPPT)-based path, for different situations based on the characteristics of the input excitation and stored energy content which are evaluated by the mode detection unit. It uses a synchronous electrical charge extraction-based self-powered passive circuit as a primary energy extraction strategy. Thus, the proposed structure is self-sustained with cold start capability. When the determined prerequisites are met, the system switches to the secondary energy extraction strategy, that is, high-efficiency MPPT-based path, in which during the maximum power point sensing phase, the PEH is sensed without disconnecting it from the interface and during the maximum power point setting phase, a bidirectional DC/DC converter performs a fully bidirectional energy transfer, increasing the extraction efficiency. The proposed system is designed and simulated using standard 180 nm complementary metal-oxide semiconductor (CMOS) technology. Post-layout simulation results show that when the input energy content is around 50 µJ, the FoM_MOPIR, periodic harvesting efficiency, shock harvesting efficiency, MPPT efficiency, and effectiveness of the proposed system are 505%, 65%, 80%, 70%, and 56%, respectively.