A Coupled Finite Element—Circuit Simulation Model for Analyzing Piezoelectric Energy Generators

A coupled finite element method (FEM) and circuit simulation approach for analyzing piezoelectric energy harvesters is presented. The advantage of the proposed method is that the mechanical analysis of the generator can be done using available FEM packages, while the circuit analysis can be performed using standard circuit simulation software (e.g., SPICE). The electromechanical coupling between the two physical domains is achieved by applying equivalent piezoelectric loads in the mechanical model, and equivalent electrical voltages in the electric model. This approach allows for the modeling of complex mechanical geometries and sophisticated, non-linear circuits. The solutions of two example problems are presented: (1) a beam generator with a resistive load, which is compared to an existing analytical solution, and (2) a plate generator with a non-linear diode bridge circuit. Though relatively easy to implement, the explicit solution technique presented in this article can be computationally expensive for complicated models with long simulation time-histories.