Low-frequency Vibration Energy Harvesting Using Magnetic Shape Memory Alloy

In this paper, a low-frequency vibration energy harvester based on magnetic shape memory alloys (MSMAs) is proposed to harvest the vibration energy. The principle of energy harvesting using the magnetic shape memory alloy is clarified, and the related experimental schematic diagram is designed. When the harvester is vibrated, the cantilever beam will exert force on the sample, which will make the martensite reorientation causing the axial magnetic polarization to change and leads to the change of magnetic flux. Therefore, when a pick-up coil is surrounded by the specimen, voltage will be induced according to Faraday's law. The magnetic field generated by the NdFeB magnet in the experimental device is simulated and verified, and the modal analysis of the cantilever beam is implemented to ensure that it can meet the requirements. Then the energy harvesting experiment is carried out and the induced voltage generated at low frequency (no more than 50 Hz) is depicted. The RMS values of the induced voltage at different frequencies are calculated. At low frequencies, the experimental results show that the proposed energy harvester has advantages in generating voltage compared with other devices, which further demonstrates the effectiveness of using magnetic shape memory alloy to capture low-frequency vibration energy and can provide references for the acoustic energy harvesting to some extent.