Wireless Energy Transmission to Piezoelectric Components

摘要

In this study, a new technique of transmitting electric energy wirelessly to piezoelectric components is explored. An electromagnetic wave is used to drive a piezoelectric plate, which is made of a lead zirconate titanate (PZT) ceramic material. The piezoelectric plate is poled along thickness direction. The proposed technique is based on the principle of coupling of an electromagnetic wave and mechanical resonance. When an electric field generated by AC voltage penetrates the piezoelectric plate, an attenuated voltage is obtained across the output electrodes of the piezoelectric plate. The power received by the electrical load connected to the output electrodes reaches maximum, when frequency of the electric field is close to the mechanical resonance frequencies of the piezoelectric plate. In the design, for the generation of electric field, an AC voltage with tunable frequency is connected to two brass electrodes mounted on a plastic plate with a tunable separation. The piezoelectric plate is inserted parallel at the center of the gap between the two brass electrodes. From the experiment it has been seen that the output power achieved by the piezoelectric plate depends upon various factors like the vibration mode, electrode pattern and electrical load of the piezoelectric component, and the electric field. At the resonance frequency, a maximum output power of 5.65 mW has been achieved by the piezoelectric plate operating in the thickness vibration mode, with input voltage of 150 V_(rms) and 4 mm gap thickness. The output power at resonance of the piezoelectric plate, operating in the thickness vibration mode, is significantly higher than that of the plate operating in the other modes like width and longitudinal vibrations.