ABSTRACT
This chapter focuses on various aspects that can limit the power density of resonant piezoelectric vibration energy harvesters (PVEHs). The energy chain in typical piezoelectric energy harvesters is depicted in a simplified manner. The chapter addresses the need for relevant metrics of comparison for PVEH system design. It investigates several ways to assess the performance of various devices. The ways are: comparing the amount of energy captured by the device with the quality of the source; and evaluating the amount of energy converted into electricity by the transducer and its energy density. Piezoelectric resonant structures can be modelled accurately using distributed parameter methods, but a simpler, lumped element approach is often sufficient and more convenient for design around a single resonant mode. Figures of merit (FOM) are proposed for benchmarking different designs, thus enabling a close comparison of different devices that have been reported in the literature.
