An improved model for Rosen type piezoelectric transformer for power converter

Piezoelectric transformer is attractive because of its small thickness. Rosen Type piezoelectric transformer has high step-up ratio which is advantageous for high voltage power converters. 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. Experimental measurements are given to show the merits of the proposed model.