Triaxial ball-impact piezoelectric converter for autonomous sensors exploiting energy harvesting from vibrations and human motion
Authors: Alghisi D., Dalola S., Ferrari M., Ferrari V.
Autors Affiliation: Univ Brescia, Dept Informat Engn, I-25123 Brescia, Italy; INO CNR, I-25123 Brescia, Italy
Abstract: A piezoelectric converter for energy harvesting composed of a rigid ball enclosed among six piezoelectric diaphragms arranged in a cube-shaped structure is presented. When the converter is excited by mechanical vibrations, the ball repeatedly bounces and hits one or more diaphragms, implementing the impact technique in a multi-degree-of-freedom configuration. The structure is isotropic thus the converter is effective irrespective of the vibration orientation. The converter is particularly suitable for energy harvesting from low-frequency random vibrations, such as those provided by human motion. The triaxial ball-impact piezoelectric converter was designed, built and experimentally characterized in the laboratory, and then tied to the ankle of a person and tested during physical activity. While the person is running at 7 km/h, a peak instantaneous power of up to 16 mW is provided by each of the six piezoelectric diaphragms, while the average power is significantly lower. The converter was coupled to a tailored power management circuit which intermittently powers a battery-less wearable temperature sensor module. In about 260 s of walking at 2 km/h, an energy of 1.4 mJ is extracted, stored into a 1-mF capacitor, and used to power the sensor module, which performs a temperature measurement and transmits the data to a receiver through a 433-MHz RF-UART link. (C) 2015 Elsevier B.V. All rights reserved.581
Journal/Review: SENSORS AND ACTUATORS A-PHYSICAL
Volume: 233 Pages from: 569 to: 581
KeyWords: Energy harvesting; Piezoelectric converter; Multi-degree-of-freedom converter; Triaxial converter; Ball impact; Frequency-up technique; Autonomous sensorDOI: 10.1016/j.sna.2015.07.020Citations: 31data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2021-10-17References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here