Magnetically modulated orbit for human motion energy harvesting

Abstract

Human energy harvesting for powering wearable or portable electronics has been extensively studied. We propose an electromagnetic energy harvester with a magnetic orbit (EMH-MO) for low-frequency and irregular human motion energy harvesting. A circular uniform low potential orbit is designed using the reasonable arrangement of multiple magnetic fields. Driven by irregular excitations, the moving magnet is magnetically modulated to move more regularly along the noncontact magnetic orbit, which is conducive to electromechanical energy conversion. A theoretical model is established to characterize the proposed energy harvester. Both simulations and experiments indicate that EMH-MO can work effectively under ultralow frequency (<5 Hz) weak excitation. The peak-peak open-circuit voltage is 4.3 V, and the average power is 0.33 mW under a reciprocating motion of 10 Hz and 20 mm. Besides, the EMH-MO can effectively harvest energy from walking, jogging, and running of people with different physical characteristics (chunky males, tall males, and petite females).