Optimal Design of Electromagnetic Energy Harvester Using Analytic Equations

• Published in: IEEE transactions on magnetics Vol. 53; no. 11; pp. 1 - 5
• Main Authors: Hyeonseok Lee, Noh, Myounggyu D., Young-Woo Park
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Current sheets; Damping; Design optimization; electromagnetic (EM) harvester; Electromagnetics; Energy consumption; energy harvester; Energy harvesting; Finite element method; Harvesters; Induced voltage; Magnetic fields; Magnetic resonance imaging; Magnetism; Magnetomechanical effects; Mathematical analysis; Mathematical model; Mathematical models; Nonlinear systems; Permanent magnets; vibration energy; Vibrations
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2017.2708130

When electromagnetic (EM) energy harvesters are designed, it is common to use finite-element analysis to investigate or verify the input-output relationships. However, it requires significant computational resources if the system is nonlinear or if it is necessary to find the time-domain behavior of the harvester. If analytic or semi-analytic equations describing the field distribution are available, it would be useful for design optimization where numerous design variations must be evaluated and compared. In this paper, the field distribution around an array of permanent magnets is obtained using the method of equivalent current sheets and the method of image sources. Then, the interaction between the magnetic force and the induced voltage is modeled as nonlinear electrical damping in contrast to a damping constant which the existing literature commonly employs. The nonlinear system model is validated against the test results obtained from a prototype EM harvester. Finally, a design optimization is performed using the proposed model, resulting in an increase in the output power by 18% from the initial design.