A Topology for Inductorless Actuation of Piezoelectric Transformer With Special Driving Waveform

The presence of an inductor during actuation of a piezoelectric transformer (PT) is a problem that has been investigated for many years. An inductorless driving topology to solve the inductor problem is proposed in this paper. This topology consists of a driver circuit and a pure piezoelectric matching network between the circuit and PT. The driver circuit is constructed to provide a specially designed waveform. The Fourier spectrum of the waveform presents dominant fundamental and third harmonics, with higher harmonics controlled to negligible levels. The third harmonic component is eliminated by a piezoelectric filter (PF), which is a component of the piezoelectric matching network. Another component is a piezoelectric inductor used to compensate for the capacitances of the PT and PF. An experimental setup is constructed to verify the performance of the driving topology. A total efficiency of 76.3% with an input power of 14.5 W is achieved when the whole driving system is considered. Although its performance is not exactly ideal, this topology is a highlight of investigations of the inductorless actuation of PTs. The proposed circuit and pure piezoelectric matching network indicate potential improvements in the performance and miniaturization of PT-based converters.