High Voltage Power Supply for Ozone Generation Based on Piezoelectric Transformer

Even though nowadays piezoelectric transformers (PT) are only available with low power rating, there exist several low power applications of ozone generation in which the use of this novel technology could be advantageous. Hence, the aim of this paper is to evaluate the possibilities of using PTs in the implementation of high voltage power supplies for ozone generation. First, the possible topologies that can be used to drive the PT are identified. Then, the half bridge inverter operating under zero voltage switching (ZVS) is investigated, and the effect of the silent discharge generator (SDG) on the converter operation is analyzed. A new control circuit that allows the ZVS operation is proposed. The control circuit operates in closed loop by measuring the phase between the PT's resonant current and the switching pattern and adjusting the switching frequency to the optimum value to assure ZVS. A laboratory prototype for a 6 W SDG was tested, and obtained experimental results are shown.