طراحی و تحلیل برداشت کننده انرژی پیزوالکتریک با عرض متغییر تحت تحریک مغناطیسی چرخان

The extraction of piezoelectric energy from rotational movements has gained attention as one of the sources of clean and sustainable energy. However, due to the low power output, optimizing these systems through various methods is of great importance to enhance their efficiency. In this paper, a piezoelectric energy harvester with indirect magnetic excitation is studied. The device consists of a cantilever beam with a piezoelectric layer, a magnet, a mass at the end of the beam, an octagonal disk connected to a rotating shaft, and driving magnets on the disk. The potential energy and nonlinear magnetic force are determined, and the electromagnetic coupling equations are extracted and incorporated into the analysis. Given the nonlinearity of the equations and the periodic nature of the oscillation, numerical methods are employed to solve the equations. Additionally, due to the main objective of the research, which is to increase voltage and output power relative to the mass of the harvester, the method of changing the end mass is used to keep the natural frequency constant by varying the tapering parameter. The effects of parameters such as the the tapering parameter, circuit resistance, and number of magnets on voltage density and output power are examined. Frequency response diagrams are plotted and analyzed to determine the effect of the rotational speed of the shaft and to investigate subharmonics and frequency conversion. The results indicate that changes in width have a sevenfold exponential effect on power density compared to a constant width.