Dynamic analysis and design of power management circuit of the nonlinear electromagnetic energy harvesting device for the automobile suspension

A nonlinear electromagnetic energy harvester (EMEH) for the automobile suspension is designed. The magnetic flux density and the magnet repulsive force of the mechanical model are determined by finite element analysis. The dynamic model of a quarter car with the nonlinear EMEH under random road excitation is established. The influence of structure parameters on output characteristics of the nonlinear EMEH is studied. In order to further improve the output power, effects of the road class, the car speed, and the load resistance are investigated in detail. Studies have revealed that the higher the road class and the larger the car speed are, the better output characteristics of the nonlinear EMEH become. In order to prove that the nonlinear magnet repulsive force can significantly improve the output power, output characteristics of the nonlinear EMEH and the linear EMEH are compared. Finally, the power management circuit matching with the nonlinear EMEH is designed, which can convert the unstable alternating voltage into the stable direct voltage, and directly supply power to electronic devices. There are two innovations in this paper. One is the introduction of the nonlinear magnet repulsive force and the amplification bar in the structural design. Another is to design the power management circuit of the high energy conversion efficiency, which is up to 74.3% for the car speed 25 m/s on the road of class C.