Development of a piezoelectric wave converter for isolated power transfer

The University of Missouri-Columbia has developed a piezoelectric wave converter for transmission of isolated power. The system is designed to deliver isolated electrical power to series solid-state switches or control electronics that "float" at high voltage. The system consists of two piezoelectric transducers attached to either end of a cylindrical acoustic waveguide. An electrical pulse applied to the input transducer excites ultrasonic pressure waves in the waveguide. Upon reaching the output transducer, the ultrasonic pressure waves are converted back to a rectified DC voltage. The system is designed to be cost competitive with existing isolation technologies. The goal of the program is to develop a 10 W-20 W module, which can transfer continuous power, and be paralleled to achieve higher powers. Initial circuit simulations using transmission line models to simulate the characteristics of the waveguide and electromechanical models of the piezoelectric transducers indicate that high efficiency transfer of isolated power is achievable using piezoelectric wave converters. Theoretical models that determine the resonant frequency of the system have also shown that operation at megahertz frequencies is achievable using commercial piezoelectric transducers. The test results are discussed and compared to the test circuit. The overall efficiency of the system versus power handling capability is optimization techniques for switched systems.