An application of piezoelectric wave converters for high voltage isolation and power transmission

The authors are currently developing an alternative means by which to deliver isolated power to serialised solid-state switches that float at high voltage. This power transmission system utilizes a novel application of piezoceramic devices to completely isolate the power signal. The system consists of a FET driven pulser which excites a lead zirconate titanate (PZT) small diameter, thin disc transducer. By means of the piezoelectric effect, the pulsed voltage excitation to the disc generates a corresponding mechanical impulse. These impulses, in the form of an ultrasonic acoustic signal, travel along the length of a solid borosilicate waveguide which is acoustic impedance-matched to the piezoceramic transducer. At the opposite end of the waveguide, a matching transducer converts the acoustic signal back into an electric power signal which can be conditioned as needed. This configuration is capable of continuously delivering power through an acoustic waveguide with a length of up to one meter. This system provides power isolation without the voltage grading effects of transformer isolation or the high cost of other isolation technologies. The operation of this system and the experimental results of its application are demonstrated in this paper