Miniature-scale energy harvesting based on the inverse magnetic shape memory effect

Article type: Research Article

Authors: Liedtke, Lukas^a | Gueltig, Marcel^a | Kohl, Manfred^a;

Affiliations: [a] Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, Karlsruhe, Germany

Correspondence: [*] Corresponding author: Manfred Kohl, Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, Postfach 3640, 76021 Karlsruhe, Germany. E-mail: [email protected]

Abstract: A miniature-scale device for harvesting of vibrational energy is presented, which is based on the inverse magnetic shape memory effect caused by stress-induced reorientation of magnetic moments. The active material is a bulk NiMnGa sample of 1 mm × 2.5 mm × 4.5 mm. A new harvester design is developed consisting of a moving magnetic circuit of mass M mounted on a spring to convert external vibrations to the active material. Thus, the deformation of the NiMnGa sample can be adjusted by tailoring the design parameters (mass M, sample dimensions, spring constant, etc.) for a given vibration source. The design and performance of first prototypes are presented showing an output power of 1.5 μW during a single load cycle at an optimum biasing magnetic field of 0.35 T.

Keywords: Vibrational energy harvesting, ferromagnetic shape memory alloy, magneto strain, NiMnGa

DOI: 10.3233/JAE-171038

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 377-383, 2019