Through-Steel Power Transmission Using Piezoelectric Transducers
Abstract
The objective of this study is to present and define a novel way of transmitting power wirelessly, by use of acoustic waves, through metal using piezoelectric transducers. Piezoelectric ceramic has the characteristic of converting an applied alternating voltage into an associated alternating mechanical movement. At a resonant frequency, efficient power transfer is achieved between opposed mating ultrasonic transducers that are coupled through a separating layer. Commercially available, off-the-shelf components were used to design a system that produced an amplified square-wave signal that was used to drive an ultrasonic transducer epoxied to a piece of ¼” thick steel plate. On the opposite side of the steel plate, another ultrasonic transducer was epoxied in the same location as the driving transducer; forming an opposed transducer-steel-transducer configuration. A rectifying circuit was connected to the receiving transducer and the resulting direct current voltage was conditioned using a DC/DC converter to produce a stable voltage to power an electrical load. Basic test equipment was used to capture signals in order to calculate transmitted and received power, and analysis and experimentation was performed to locate resonant frequencies that produced peak power transfer efficiencies. Power transfer efficiencies of xv up to 65% were achieved and over 10 Watts of power were sourced to a resistive test load connected to the output circuit of the receiving transducer. Results of this magnitude represent a significant finding, especially given the low cost and simple design of the system.