Significant power enhancement method of magneto-piezoelectric energy harvester through directional optimization of magnetization for autonomous IIoT platform

• Published in: Applied energy Vol. 254; p. 113710
• Main Authors: Cho, Jae Yong, Kim, Jihoon, Kim, Kyung-Bum, Ryu, Chul Hee, Hwang, Wonseop, Lee, Tae Hee, Sung, Tae Hyun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.11.2019
• Subjects: Autonomous; Lorentz force; Magnetic field; Piezoelectric energy harvester; Power cable; Wireless sensor network; Wireless sensor network; Power cable; Lorentz force; Piezoelectric energy harvester; Autonomous; Magnetic field
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2019.113710

•The directional optimization of magnetization was considered to enhance output power.•The harvester generated 39.2 mW as 2.13 to 784 times enhanced power.•The autonomous IoT and IIoT sensor systems were successfully constructed.•This method can significantly improve the energy harvesting using a magnetic field. Unlike previous piezoelectric energy harvesters that generate electrical energy from a magnetic field according to the magnetic strength or magnetostrictive material, the proposed method achieves significant power enhancement using directional optimization of magnetization. This method can serve as a ubiquitous autonomous energy source that converts a magnetic field into usable electrical energy in a wireless sensor network for an (Industrial) Internet of Things (IIoT). The key approach in the proposed model is to increase of the Lorentz force by vertically adjusting the magnetic flux direction of a power cable and the magnetic direction of a tip magnet. In the simulation, a 3592 times higher y-axis Lorentz force was obtained in the vertical pole array, which resulted in about a 1.6 times higher output voltage. Then, we experimentally compared the electrical output performance of six different types of pole array according to the size and direction of the tip magnet. In a one-tip magnet (10 × 10 × 10 mm3), the output power values were 2.34 mW (Vertical) and 1.23 mW (Horizontal) at 8 kΩ matching impedance. For two-tip magnets (20 × 10 × 10 mm3), the output power values of the harvester were 39.2 mW (Planar-Vertical), 18.4 mW (Orthogonal-Vertical), 8.64 mW (Planar-Horizontal), and 0.05 mW (Orthogonal-Horizontal) at 5 kΩ matching impedance. It was found that the power generation differed by 2.13 to 784 times. With this method of power enhancement using multi-disciplinary research, we successfully constructed autonomous IoT and IIoT sensor systems for smart homes, smart buildings and smart factories.