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In-Wheel Piezoelectric DC Power Generator With Zero Resistive Torque.
Hyun Soo Kim1,2, Hyunseok Song3, In Woo Oh1,4
1Electronic and Hybrid Material Research Center, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.
Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
|January 28, 2026
Summary
This study introduces a novel direct-current piezoelectric generator (DC-PG) for efficient, small-scale power. The innovative design offers a practical solution for self-powered Internet of Things (IoT) devices in low-load environments.
Area of Science:
- Energy Harvesting
- Materials Science
- Mechanical Engineering
Background:
- Conventional electromagnetic generators face limitations in low-power applications due to mechanical complexity, bulkiness, and reduced efficiency at small scales.
- Resistive torque from Lenz's law further compromises performance in low-load environments, limiting suitability for certain applications.
Purpose of the Study:
- To propose and evaluate a novel in-wheel direct-current piezoelectric generator (DC-PG) that overcomes the limitations of conventional generators.
- To demonstrate efficient power generation with zero resistive torque and no need for rectification, suitable for low-load conditions.
Main Methods:
- Development of an in-wheel direct-current piezoelectric generator (DC-PG) utilizing continuous in-phase polarization during rotation.
- Integration of the DC-PG into a suitcase wheel without adding significant weight or volume.
- Testing under realistic conditions with a 20 kg load at 3-5 km/h to measure peak power output and charging capability.
Main Results:
- The DC-PG achieved a peak power of 4.28 mW under realistic conditions, outperforming conventional AC-based piezoelectric systems.
- The generator delivered a stable, low-ripple DC output with minimal energy loss, requiring no rectification.
- Successfully powered a wireless Internet of Things (IoT) location sensor, charging a 5 V capacitor in 134 seconds.
Conclusions:
- The compact, rectification-free DC-PG is a viable solution for efficient small-scale power generation and self-powered IoT applications.
- Elimination of electromagnetic resistance and high efficiency enable energy autonomy in low-speed, low-load environments.
- This technology opens new possibilities for sustainable power in portable electronics and sensor networks.
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