Parameter identification for resonant piezoelectric energy harvesters in the low- and high-coupling regimes

Abstract

We demonstrate a method for identifying the parameters of piezoelectric harvesters by simple electrical measurements. The basic equations are derived from a simplified yet accurate model. The accuracy of the model is proven by comparison with the full model. Two beam harvesters, one with a unimorph beam and one with a bimorph beam, have been fabricated and characterized. The results coincide well with proposed theory and demonstrate the differences between harvesters with low and high coupling constants. It turns out that four parameters are sufficient to completely describe the electrical behavior of a harvester with a low coupling constant. For harvesters with high coupling constants, five parameters are needed.