Hybrid piezoelectric-triboelectric vibration energy harvester for intelligent bearing self-powered system

Abstract A hybrid piezoelectric-triboelectric vibration energy harvester for the intelligent bearing self-powered system is proposed. To address the problems of limited applications of battery-powered condition monitoring devices in the intelligent bearing’s radially slotted outer ring structure. By collecting the bearing elastic vibration energy, converting it into electrical energy, and supplying it to the condition monitoring equipment, the self-powering of the intelligent bearing condition monitoring equipment can be realized. The energy harvester is based on a triangular single-crystal piezoelectric cantilever beam with double mass blocks, and two nanogenerators with limiting functions are organically integrated with the vibration direction of the cantilever beam. The composite co-generation of piezoelectric and triboelectric modes during vibration and limit collisions is realized. The space is effectively utilized, and the output performance is improved. Meanwhile, the electromechanical coupling dynamic model of the energy harvester is established by using the centralized parameter method. The effects of different structures and dimensions on the natural frequency and output voltage of the piezoelectric cantilever beam are analyzed by simulation. The accuracy of the electromechanical coupling dynamics model and simulation analysis is also verified through experiments. The experimental results show that the proposed hybrid piezoelectric-triboelectric vibration energy harvester can work effectively within the normal operating vibration acceleration range of 0 ∼ 28.2 m s −2 of the intelligent bearing. At an acceleration of 2 m s −2 , the maximum peak-to-peak values of the open-circuit output voltages of the piezoelectric and triboelectric units of the harvester are 1.28 V and 1.05 V respectively. At an acceleration of 20 m s −2 , the maximum peak-to-peak values of the open-circuit output voltages of the piezoelectric and triboelectric units of the harvester are 2.85 V and 1.18 V respectively. As the vibration acceleration of the intelligent bearing increases, the response voltage amplitude also increases. However, no matter how the response voltage amplitude changes, the output voltage fluctuates around 3 V after the energy harvesting circuit.