4. Electromechanical-electrical conversion (electrical transformer)

4.1 General

The first piezoelectric transformer (PT) structures appeared in the 1950s, following work by Charles A. Rosen at Syracuse University in the USA. Rosen at Syracuse University in the United States. These early transformers, which today bear his name, were able to achieve a high voltage rise, thanks to the aspect ratio between primary and secondary, but had a low power density (5 W/cm ³ ) and were very fragile. 50 years on, this technology has become the one that looks set to replace electromagnetic transformers in certain specific applications, thanks in particular to its energy conversion principle, which uses acoustic waves, and its compact structure.

Various piezoelectric transformer structures are available....