A Frequency Up-Converted Hybrid Energy Harvester Using Transverse Impact-Driven Piezoelectric Bimorph for Human-Limb...

Area of Science:

• Energy harvesting
• Biomedical engineering
• Mechanical engineering

Background:

• Human-body motion is typically low-frequency and high-amplitude, posing challenges for conventional energy harvesters.
• Mechanical impact can achieve frequency up-conversion for energy harvesting but risks damaging transducer elements.
• Existing hybrid harvesters often lack robust mechanisms for reliable frequency up-conversion.

Purpose of the Study:

• To propose a novel transverse mechanical impact-driven frequency up-converted hybrid energy harvester.
• To integrate piezoelectric and electromagnetic transducers for enhanced energy harvesting from human limb motion.
• To improve power density and reliability in energy harvesters for wearable applications.

Main Methods:

• A hybrid energy harvester design utilizing a freely-movable sphere for transverse impact on a seismic mass.
• Integration of a piezoelectric bimorph beam and electromagnetic induction within a compact device.
• Development and experimental validation of a mathematical model for harvester performance prediction.

Main Results:

• The hybrid harvester achieved maximum average powers of 93 µW (piezoelectric) and 61 µW (electromagnetic) at 5.2 Hz limb motion.
• An average power density of 8 µW·cm⁻³ was obtained, demonstrating significant energy harvesting capability.
• Successful demonstration of powering low-power electronics using AC-DC converters.

Conclusions:

• The proposed transverse impact-driven hybrid energy harvester effectively addresses challenges in harvesting energy from human motion.
• Integration of dual transducers enhances power output and power density.
• The device shows promise for self-powered wearable electronics and low-power applications.