An improved piezoelectric transformer model with parallel connection feature

Piezoelectric transformer is attractive because of its small thickness. In most cases the load has a range of variable resistances that can greatly affect the output characteristic of a piezoelectric transformer. The conventional model is not sufficient to model the gain characteristics with a wide load range. In this paper a modified model is presented. A simple fictitious resistor is employed to modify the conventional model and it produces excellent match with measurements. This model is further extended to model parallel connection of PTs with the aim to increase output power. Experimental measurements are given to show the merits of the proposed model.