An insight into centrifugal force and magnetic nonlinearity benefiting for beam-type energy harvesters in rotational motion

Recently, energy harvesting has been utilized as an alternative to provide sustainable power supply for wireless sensors in Internet of Things (IoT). Due to the advantages of simple structure and high energy conversion efficiency in rotational environment, beam-type energy harvesters with magnetic nonlinearity have attracted much attention. However, few studies revealed the joint mechanism of the centrifugal force and the magnetic nonlinearity. To fill this gap, this paper originally illustrates the influences of the centrifugal force and the magnetic nonlinearity on power generation of beam-type piezoelectric energy harvesters (PEH). A comprehensive mathematical model considering the installation angle of the beam-type PEH is proposed. Based on that, the centrifugal force and the magnetic force are theoretically investigated. In addition, their joint mechanism is also analyzed. The findings demonstrate that the centrifugal force can change the beam stiffness depending on the installation angle, and the magnetic nonlinearity contributing to multi-stability can decrease the requirement of the exciting force. In summary, this insight is guidance for the future design of beam-type energy harvesters with high-efficiency power generation.