Modeling and Analysis of a Non-linear Electret Electrostatic Energy Harvester

With the rapid development of MEMS and CMOS sensors and improvement of data processing capabilities we have entered the era of the internet of everything (IoE), and the ensuing problem of sensor power supply has attracted more and more people's attention. Vibration energy harvester that can directly convert vibration energy into electrical energy from the environment have become hot topics in recent years because of the short life, large size, long-term storage and other shortcomings of traditional chemical batteries. The electrostatic vibration energy harvester is a typical harvester, which always uses beam structure to capture the environmental energy. However the working bandwidth of traditional beam is always relatively narrow, while the vibration frequency range of environment is relatively wide. Thus the capture energy efficiency of traditional beam structure is relatively low. In this paper, a nonlinear method is introduced into electret electrostatic energy harvester, which employed magnetic body structure to introduce nonlinear force. In the paper, the model of this nonlinear harvest is built, and its characteristics are analyzed. According the analysis result, magnetic force introduced can improve capture energy bandwidth, moreover, repulsive force expands the bandwidth larger than attractive force.