Broadband Rotational Energy Harvesting Using Micro Energy Harvester

This paper proposes a broadband rotational energy harvesting setup by using micro piezoelectric energy harvester (PEH). When driven in different rotating speed, the PEH can output relatively high power which exhibits the phenomenon of frequency up-conversion transforming the low frequency of rotation into the high frequency of resonant vibration. It aims to power self-powered devices used in the applications, like smart tires, smart bearings, and health monitoring sensors on rotational machines. Through the excitation of the rotary magnetic repulsion, the cantilever beam presents periodically damped oscillation. Under the rotational excitation, the maximum output voltage and power of PEH with optimal impedance is 28.2 Vpp and 663 μW, respectively. The output performance of the same energy harvester driven in ordinary vibrational based excitation is compared with rotational oscillation under open circuit condition. The maximum output voltage under 2.5g acceleration level of vibration is 27.54 Vpp while the peak output voltage of 36.5 Vpp in rotational excitation (in 265 rpm).