Ultrasound vibration energy harvesting from a rotary-type piezoelectric ultrasonic actuator

Abstract

Ultrasound vibrations, which are abundant in our everyday environment, have long been widely used in industrial applications and medical therapeutics. While there have massive number of studies on harvesting the low-frequency vibration energy to power the low-powered electronic devices, there are few literatures on the ultrasound vibration energy harvesting. In order to validate the feasibility of ultrasound vibration energy harvesting, this article takes a rotary-type piezoelectric ultrasound actuator (PUA) as the research object, a new PZT ring with appropriate zoning and polarization is bonded onto its elastomer top surface to harvest the vibration energy induced by the ultrasound waves. The manufacturing process and operating mechanism of the modified PUA are firstly introduced. Then, the electromechanical coupled model is derived based on the equivalent circuit method, and the dynamic and energetic characteristics of the ultrasound vibration energy harvesting under three excitation modes (i.e., two standing waves and one traveling wave excitations) are theoretically studied. The experimental results testify the theoretical values, and the feasibility of ultrasound vibration energy harvesting is also validated by experiments and an application example. When the PUA is excited by traveling ultrasound wave with amplitude 67 V and frequency 35.1 kHz, the maximum harvested power of each sector of the new PZT ring and λ/4 sector of the bottom PZT ring reach 58 mW and 82.4 mW, respectively, which fully meet the power supplying requirements of low-powered electronic products and implantable medical systems.