Design of Rectified Piezoelectric Power Generators by Finite Element Methods

The article proposes designing rectified piezoelectric power generators based on the direct finite element method. It accounts for the consideration of common interface circuits such as the standard and parallel-/series-SSHI (synchronized switch harvesting on inductor) circuits, and complicated structural configurations such as arrays of piezoelectric oscillators. The proposed model suggests replacing the energy harvesting circuit by an equivalent load impedance in series with negative piezoelectric capacitance. As the expression of the equivalent load impedance can be explicitly derived, the proposed finite element approach is capable of handling common interface circuits without resorting to circuit solvers. Finally, the model is extended to the consideration of SECE (synchronized electric charge extraction) circuit which offers an advantage of independence of harvested power on external loads.