Design of the fixed frequency controlled piezoelectric transformer based DC/DC converter

Piezoelectric transformers (PTs) converters show some difficulties to work in the case of the variable load at fixed frequency. PTs can be designed to achieve these problems, but the size of the PT may become larger. In fact, the selection of the circuit topologies and the control methods influence the size and the efficiency of the PT converter. Two rectifiers (half-wave rectifier and the full-wave rectifier) were compared and two control methods (PWM control and burst mode control) were compared according to the efficiency of the converter. The full-wave rectifier and the burst-mode hysteresis control are the better choice. The hysteresis control was also proposed to improve the dynamic response of the burst-mode control.