| This thesis presents an equivalent circuit model for a Rosen type piezoelectric transformer. Transmission line equations for various vibration modes with a clamped boundary condition on one end of each section are developed. The partial expansion theorem is used to convert the transmission line model into an equivalent circuit model. Losses are introduced in a post-processing step using the experimental value of mechanical quality factor. L'Hospitals rule is used to simplify the circuit near a desired resonance frequency. Experimental results confirm the existence of multimode resonance and anti-resonance behavior. The modeling methodology is then extended to multi-layered rectangular and circular geometries.;The applicability of two DC-DC converter topologies in connection with a piezoelectric transformer i.e. Class-E and an Asymmetrical converter are discussed. Also, experiments on a three winding multi-layered device connected to an asymmetrical converter are performed. Results indicate that the third winding cannot be used to provide a feedback voltage since the voltage does not track the secondary output voltage. |
