Presentation of a new equivalent circuit of a piezoelectric transformer under high-power operation

In this paper, the power transmission characteristics of a piezoelectric transformer are considered. As a result, the following has been clarified: the frequency of the maximum step-up voltage ratio coincided with the resonance frequency, and the frequency of maximum efficiency approximately coincided with the intermediate frequency between the resonance and anti-resonance frequencies. However, conventional equivalent circuits cannot represent these phenomena, In this paper, we have proposed an improved equivalent circuit that was useful for presenting the tendency of the experimental results. The specific future of this circuit is that the series and parallel resistances that present high-power operation loss are included. The method used to derive the proposed equivalent circuit is described and some experimental and calculated results are shown.