Performance Analysis of Low-Frequency Piezoelectric Energy Harvesting Systems with Multiple Nonlinear Factors and Bidirectional Excitations

With the swift advancement of microelectronic technology and MEMS, piezoelectric energy harvesting technology has garnered escalating attention due to its eco-friendly and sustainable attributes. In this paper, a bimorph piezoelectric energy harvesting system considering multi-nonlinearity complex factors is devised, and the approximate analytical solutions for vertical displacement, output voltage, and output power of the entire system are derived. Owing to inherent nonlinear softening characteristic of material nonlinearity, the effective frequency bandwidth of the energy harvesting system is significantly broadened. The result indicates that under horizontal excitation ranging from 0.2g to 0.3g, the peak output voltage of the energy harvesting system with a frequency of 3.2254Hz (open circuit) increases approximately by 7.9 times. At another frequency of 3.2054Hz (short circuit), the peak output voltage amplitude is multiplied by approximately 6.5 times. Considering material nonlinearity, it can be concluded that the system energy harvesting efficiency at low frequency can be greatly improved. The numerical result obtained is not only more accurate, but it is also more consistent with real situations. This conclusion provides a theoretical basis for research and analysis of similar systems in low-frequency ranges.