Piezoelectric transformer operating in thickness extensional vibration and its application to switching converter

A new type of piezoelectric transformer (PT) power converter incorporating the ZVS technique is presented. A combination of the ZVS technique and the PT successfully achieves higher efficiency. For low output voltage, using half-bridge rectifier stage, the converter achieved 72% efficiency, at V/sub in/=80 V, V/sub o/=11.8 V, and P/sub o/=5 W. For medium output voltage, using full-bridge rectifier stage, the converter achieved 83% efficiency at V/sub in/=80 V, V/sub o/=40 V, and P/sub o/=10.7 W.<
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