Energy recovery DC/AC converter for piezoelectric transformer

Piezoelectric transformers have been used successfully in DC/AC or DC/DC converter. However, the use of piezoelectric transformers presents a major challenges for power electronic design: the capacitive nature of such devices makes their use delicate as the instantaneous power may be much greater than the average effective power. Due to this challenge, conventional drive circuits, especially inductor, become too bulky. This work describes a converter suitable to drive piezoelectric transformer with low inductor. The proposed converter is a DC/AC structure, which is capable of producing a unipolar square voltage. The circuit provides for recovery of the energy stored on the clamped capacitance back to the primary power supply when the transformer is de-energized. In our design, an auxiliary shunt circuits are connected to the input terminal. The proposed structure of both theoretical and experimental validations has demonstrated the effectiveness of the proposed technique for recovery energy.