Parallel connection of resonant converters based on piezoelectric transformers

One of the most important advantages in using piezoelectric transformers (PT) is that they operate at high frequencies with a very good efficiency, tipically higher than 95%. This paper presents a DC/DC converter based on two piezoelectric transformers which duplicates the output voltage frequency ripple, maintaining the switching frequency. Also, the converter operates at a fixed frequency, and an alternative way to regulate the output power is shown. The converter is achieved by parallelizing two DC/DC converters, based on piezoelectric transformers. Of course, the size is increased, but on the other hand, the efficiency and the output ripple are improved. The obtained results evince an improvement in the overall efficiency, as well as a reduction in the output filter size, with a lower voltage ripple.