Resonant current estimation and voltage regulation for piezoelectric transformer-based power supply

This paper proposes an output voltage regulation approach for a piezoelectric transformer (PT)-based power converter. The inductorless half-bridge configuration is employed to achieve zero-voltage switching. A resonant current estimation circuit is implemented at the output section of the PT, and it is used by a phase-locked loop (PLL) zero voltage switching (ZVS) controller to synchronise MOSFET switching to the zero crossings of the resonant current. Burst-mode control is employed to provide output voltage regulation of the DC/DC converter. Both experimental and simulation results demonstrate the operation of the system.