Assessment of parameters of the vibration-based energy harvesting system located in the micro-power generator

This article presents the optimisation process of some key parameters such as the size of the macro-fibre composite (MFC) and the optimal impedance load matching the piezoelectric harvester located in the prototype of the micro-power generator to enhance the vibration-based energy harvesting effect. For this, the distributed parameter model of this structure, including MFCs of the 8514 P2, 5628 P2 and 8528 P2 types, with a homogenous material in the piezoelectric fibre layer was determined. The numerical analysis of the FEM model of the flexure strip with piezo-composite indicated that the highest amplitude of voltage >7 V is generated by the proposed device with the piezo of the 8528 P2 type, while the lowest amplitude (close to 1.1 V) was noted for the piezo of the 8514 P2 type. Experiments were carried out on the laboratory stand to verify the obtained results. In addition, it was shown that the power output of the real EH system with the piezo of the MFC 8528 type, connecting with the matched resistive load (R = 120 kΩ), led to a significant increase in the value of the generating voltage up to 500 mW versus EH system with the piezo of 8514 P2 and 5628 P2 types. Finally, the effectiveness of this system was found to be close to 33% for the EH system with the piezo of the 8528 P2 type.