Coexistence Mechanism of Bi-Stability and Resonance in Piezoelectric Energy Harvesters Through Total Energy Analysis

Bistable piezoelectric energy harvesters are of great interest due to its excellent responsivity in the low and varying frequency range. This paper presents the total energy theory to analyze bistable systems. Different from the previous optimization method to merely adjust the bistable potential energy function, in this paper, both kinetic and potential energy dimensions are incorporated from the energy point of view. Based on this, we propose the coexistence mechanism of bi-stability and resonance, and demonstrate that the coexistence can improve the kinetic energy of the system and thus enhance the output power. Near the resonant frequency, the kinetic energy can be boosted by 206%, causing a potential energy boost of 210%. And for internal resistance of 0.8, the maximum average power is increased by 192.86%. The results show that kinetic energy has a great influence on improving the output power of the system. The perspective of total energy analysis plays an extremely important role in boosting power of a bistable system.