Design and Experiment of Piezoelectric–Electromagnetic Composite Energy Trap Based on Human Motion

Abstract

To realize the harvesting of energy generated by human movement, in this study, a piezoelectric–electromagnetic composite was designed for harvesting the energy generated by low-frequency human motion is designed by combining the principle of power generation and electromagnetic energy conversion of polyvinylidene fluoride (PVDF) piezoelectric materials. First, the structure and working principle of the piezoelectric–electromagnetic composite energy trap were designed and analyzed. Next, the system dynamics model of piezoelectric–electromagnetic coupling power generation was established, and the main influencing factors of the composite energy trap were derived. Moreover, the influence of PVDF piezoelectric materials with different size parameters on the output voltage and the influence of the frequency of the moving permanent magnet on electromagnetic power generation were analyzed. Finally, the prototype was constructed and tested. The results revealed that the output voltage of the piezoelectric–electromagnetic composite energy trap placed horizontally is higher than that of the composite energy trap placed vertically at step frequencies of over 90 steps/min, and the maximum output voltage is 25.6 V at the step frequency of 140 steps/min. The electric energy generated by the composite energy trap can supply power to low-power electronic devices, thus demonstrating the feasibility of collecting human-motion energy for power generation.