Study of mass effect in electromechanical modelling of piezoelectric energy harvesters.

There is a growing interest in the evolution of energy harvesting techniques. The main reason for this demand is the industrial digitalization we are experiencing, which creates the need for sustainable and versatile energy sources. Traditionally, the use of wired or battery systems has encountered limitations in terms of accessibility to certain places and recyclability. This is where energy harvesting techniques capable of extracting energy from the environment and converting it into electrical power sources find their place. Piezoelectric harvesters can convert mechanical deformation energy into electrical current. However, they have their limitations in the power capacity they can deliver. Therefore, different formulas are investigated to optimize the extracted energy. One of the most successful is to add masses to the harvester to force a greater deformation when it is subjected to vibration. The objective of this research work is to study how the addition of different masses and their positioning affects a piezoelectric harvester. For this purpose, a series of experiments have been done with different mass configurations. As a result, the mass effect in every harvester configuration has been parametrized and several differences have been identified. The detection of a 53% increase in the mass effect ratio for a specific harvester thickness stands out. The conclusions of this research work are related to the use of electromechanical parameters with the objective of evaluating and predicting the behavior of the harvester and its energy extraction capacity with the addition of masses.