Operating frequency characteristics of piezoelectric high-voltage power supply converter

The operating frequency characteristics of high-voltage power supply converter based on piezoelectric transformer (PT) is researched. The analysis of fundamental wave was used to get the equivalent model of converter output circuit and then the frequency characteristics of converter were investigated in the process of charging. It is found that the output equivalent capacitance increases with the increase of the operating periods. The equivalent resistance prompts rapidly with the increase of operating periods and achieves the maximum, then descends slowly and tends to a steady-state. In the whole process of the converter charging, the converter operating frequency descends with the increment of operating period, but the change is small, the operating frequency is only changed about 0.8 kHz in 90000 operating periods (about 1.1 socend).