Piezoelectric transformer parameters evaluation

Power electronic circuits have traditionally been based on magnetic technology. The transformers and inductors in conventional converters are usually bulky compared to other elements. In an effort to miniaturize power components a piezoelectric, rather than a magnetic transformer could be employed in the power supplies. A single-branch equivalent circuit model can characterize all types of piezoelectric transformers (PT) within a specific frequency bandwidth around the corresponding mechanical resonant frequency. Its equivalent parameters should be obtained experimentally. New method for obtaining PT equivalent parameters from physical measurements is proposed in this paper. It was verified by simulation and experiment. It is shown that phase matching approach together with properly constructed measurement scheme gives an excellent agreement between measured and reconstructed transfer function of PT.