Recent Developments of Piezoelectric Energy Harvester for Scavenging Vibration Energy

The increasing reliance on non-renewable energy sources has led to severe environmental challenges, including pollution and a global energy crisis. These pressing issues have motivated researchers to develop and explore alternative energy harvesting systems capable of capturing ambient energy from the surrounding environment. One promising solution is the use of piezoelectric energy harvesters (PEHs), which generate electrical energy in response to mechanical pressure or vibrations. These devices typically incorporate piezoelectric materials mounted on mechanical structures, such as cantilever beams or flexible plates, which deform under external excitations. This deformation produces strain within the material, inducing the piezoelectric effect and resulting in electricity generation. This paper reviews and compares five of our previous studies focusing on different mechanical excitation mechanisms for enhancing the performance of piezoelectric energy harvesters. Specifically, we investigate and analyse three methods: direct collision, vortex-induced vibration (VIV), and rotational-based collision. Each method involves distinct excitation elements and physical interactions, such as varying mass weights, gravitational force, fluid-induced vortices, deflection of cantilevers, momentum transfer, and impulse forces. By evaluating the influence of these excitation characteristics on the resulting voltage outputs, we identify the key parameters that contribute to efficient energy harvesting. The findings highlight the importance of the interaction between mechanical components and the piezoelectric materials. This work provides valuable insights for the development of next-generation self-powered systems and low-power electronics that rely on sustainable and renewable energy sources from ambient mechanical vibrations.