Rotary Multimodal Energy Harvesting Device

Abstract

In this paper, a new multimodal energy harvesting device consisting of two transduction mechanisms and having unique properties at various operating modes is presented. The hybrid system includes electromagnetic and piezoelectric energy harvesting technologies, and uses linear motion and impact forces from human motion for energy harvesting. The device is based on an unbalanced electromagnetic rotor made of three beams of piezoelectric material that have magnets attached to the ends. The device is to be worn on the legs or arms of a person. Linear motion, from the arms or legs swinging, causes the rotor to spin and the magnets to pass over the coils. Impact forces, from stepping, induce stress on the piezoelectrics which generates voltage across the electrode. The results of several numerical simulations are presented. For the piezoelectric beams, numerical simulations were done to find the deflection, stress, optimum operating frequency, and mode shapes taking into account environmental conditions. For the electromagnetic generation, numerical simulations were done to find the optimal load resistance and power generation for several different orientations. Other design related issues will also be investigated to fully realize the device in real world applications.

Characterization of a rotary hybrid multimodal energy harvester

“…The model developed for the EM generation of the device was presented in a previous work [24]. The model had an initial condition for the rotor continuously spinning of an initial angular velocity greater than the frequency of the driving oscillation.…”

“…The desired range of operation for the device was 1-10 Hz, the most dominant frequency range of human motion, for the majority of the power generation with an extended range of up to 30 Hz, the range of frequency a person would encounter riding in a car [20]. The initial design, modeling, and simulations were presented in the previous work [24,25].…”