Theoretical and experimental studies on piezoelectric-electromagnetic hybrid vibration energy harvester

In order to improve the performance of vibration energy harvester (VEH), multiple electromechanical transducers based hybrid vibration energy harvester (HVEH) has been proposed by some researchers. In this paper, we focus on the piezoelectric-electromagnetic HVEH and established the theoretical model for the HVEH with Hamilton's principle. The established theoretical model shows that the performance of the HVEH is not equal to the sum of the two stand-alone VEH, and the equivalent electrical damping of the HVEH can also not be directly expressed as the sum of the two equivalent electrical damping of the stand-alone VEH. These are different from the existing theoretical model. To verify the established model, a piezoelectric-electromagnetic HVEH was fabricated and tested. The power output of the fabricated HVEH is 57.24 W. Experimental results show that the power output of the HVEH is less than the sum power output of the two stand-alone VEH, but is higher than power output of any one stand-alone VEH, which is agree with the established theoretical model.