Variants and hybrid interfaces
Electrical interfaces for piezoelectric mechanical energy harvesting devices

Without being totally exhaustive, this section aims to outline the main variants and hybridizations of the SSHI and SECE interfaces. While the techniques discussed above are mainly aimed at improving power recovery for low coupling and/or high damping, or, to some extent, ensuring impedance to the load while benefiting from a gain over the conventional approach, other challenges are emerging in the real-world application of microgenerators. The main challenges include

• mastering the trade-off between power gain and load independence,

• control of the trade-off between extracted energy and available energy (cushioning effect),

• the ability to recover over a wide frequency range.