A magnetoelectric energy harvester for low-frequency vibrations and human walking

Abstract

This paper proposes a magnetoelectric (ME) energy harvester employing a ME transducer array to capture mechanical energy from low-frequency vibrations and human walking. The use of the double-ring Halbach array helps to enhance the magnetic flux density in the air gap where the ME transducer array is placed. Consequently, larger magnetic field variations are induced on the ME transducer array and more mechanical energy can be converted into electrical energy. A theoretical model is developed and verified by experiments under sinusoidal excitations. The experimental results show that the harvester exhibits broad 3 dB bandwidths for sweep-up and sweep-down conditions. A 3 dB bandwidth of 4.1 Hz is obtained at the acceleration of 0.3 g, indicating that he harvester can operate in a broad bandwidth. The harvester can produce a maximal power of 0.667 mW across an optimal resistive load of 1.52MΩ at 0.3 g. Moreover, the feasibility of the harvester under human-walking induced excitations is experimentally validated at the speed of 3–8 km/h, and the results demonstrate the potential application of the proposed ME energy harvester in powering portable electronic devices.