Enhanced piezoelectric energy harvester performance using magnetic force and thermal energy

One possible approach of improving the performance of energy harvesters is to use energy harvester with an external magnetic force to create a nonlinear coupling system. In this work, we report experimental results of a single piezoelectric cantilever beam (PCB) with tip mass or conventional piezoelectric energy harvester (CPEH), and the effect of applying an external magnetic force. The output voltage and power at optimal resistance was 7.62V and 0.62mW, respectively, at the resonance frequency of approximately 11Hz of a CPEH. Also, the output voltage and average power at optimal resistance was 8.56V and 0.44mW, respectively, at resonance frequency of 7Hz of a PCB with fixed opposing magnet. Furthermore, the output voltage and average power at optimal resistance was 13.31V and 1.77mW, respectively, at resonance frequency of 11Hz of a PCB with opposing magnet attached at a second cantilever. In addition, comparison between the experimental results of all different configurations showed a reasonable enhancement of performance of energy harvester when an external magnetic force added over the main PCB. Finally, the performance of a multisource energy harvester with magnetic, thermal and mechanical sources is also presented in this study. In this case, it is demonstrated that increase in output voltage with temperature gradient under effect of magnetic force; the results of 2(nd) and 3(rd) model showed 44% and 99% enhancement of its original output voltage value at 1.2 degrees C and 2.7 degrees C temperature difference, respectively.