An implicitly coupled finite element-electronic circuit simulator method for efficient system simulations of piezoelectric energy harvesters

A piezoelectric vibration-based energy harvester (PVEH) consists of an electromechanical structure and an electric circuit, influencing each other. The finite element method (FEM) allows for the simulation of arbitrarily shaped and nonlinear electromechanical structures, while an electronic circuit simulator (ECS) can be applied to simulate arbitrary electric circuits. We propose a novel implicit FEM-ECS coupling method, which combines the advantages of the FEM and the flexibility of an ECS. The Newton-Raphson method is applied to achieve rapid convergence at the interface between the FEM and ECS simulations, so that arbitrary PVEHs can be efficiently analyzed. The new implicit FEM-ECS coupling is validated against explicitly and monolithically coupled FEM-ECS simulations of PVEHs from literature. Moreover, an application example consisting of a nonlinear electromechanical structure and a self-powered SSHI circuit is considered and a shock-like base excitation is applied. The examples demonstrate the practical applicability of the novel coupling method for realistic simulations of PVEHs.