Theoretical modeling and experimental verification of rotational variable reluctance energy harvesters

• Published in: Energy conversion and management 2021-04, Vol.233, p.113906, Article 113906
• Main Authors: Zhang, Ying, Zhu, Hongyu, Xu, Ye, Cao, Junyi, Bader, Sebastian, Oelmann, Bengt
• Format: Article
• Language: English
• Subjects: Air–gap magnetic permeance; Coils; Electric potential; Energy; Energy harvesting; Energy harvestingVariable reluctance; Low speed; Magnetic circuits; Magnetic fields; Magnetic flux; Magnetic permeance; Mathematical analysis; Performance prediction; Rotational motion; Theoretical modeling; Transducers; Variable reluctance; Voltage
• ISSN: 0196-8904; 1879-2227; 1879-2227
• DOI: 10.1016/j.enconman.2021.113906

•A new modeling method for variable reluctance energy harvester is proposed.•A SA-MFD method is presented to accurately calculate air–gap magnetic permeance.•Numerical and experimental results verify the proposed model to predict voltage.•The measurement shows that the average power can achieve 46.7 mW under 300 rpm. Energy harvesting has great potential for powering low-power wireless sensor nodes by converting environmental energies into the electricity. It can be widely used for real-time online industrial monitoring. Among different transducers, the variable reluctance energy harvester (VREH) has attracted much attention due to the great performance for the low-speed rotations. However, there is a lack of precise models for performance prediction. In this paper, a new modeling method for VREH is proposed to predict the output voltage. A combined Substituting Angle - Magnetic Field Division modeling method is presented to accurately model the magnetic permeance of the air–gap for the VREH. Then, the magnetic flux change in the magnetic circuit is derived to calculate the voltage response of the coil. The numerical and experimental results of voltage responses verify the effectiveness of proposed model with the maximum error of 4%. The influence of some key factors on voltage response is investigated, including the thickness of air–gap and tooth height. Moreover, power analysis demonstrates that the output power increases from 5.06 mW to 46.7 mW with the rotational speed from 100 rpm to 300 rpm.