Transient response of vibration energy harvester incorporating inertial rotation structure

The transient response of a vibration energy harvester incorporating an inertial rotation structure is investigated. The inertial rotation structure is used to realize electromagnetic conversion, where the rotational kinetic energy is transformed into electrical energy, as described by the Faraday law. The dynamic effects of such rotation structure on the mechanical system are separated into two parts: the modified inertance and additional damping. The modified inertance changes the system resonant frequency, while the additional damping reflects the mechanical energy dissipation and electric energy generation. The influences of system parameters on the performance of the harvester are analyzed. Under the transient excitation, the output power initially increases and decreases after the peak power. The additional inertance from the inertial rotation structure has a negative role in the vibration energy harvesting. The friction between the rack and gear is also considered, which dissipates the mechanical energy, suppresses the responses, and reduces the output power. The results of the proposed method are compared to those of a Monte Carlo simulation. The coincidence of the theoretical and numerical curves demonstrates the accuracy of the proposed method. These results will guide the design of a vibration energy harvester incorporating an inertial rotation structure for transient energy sources.