Equivalent Impedance Electroelastic Modeling of Multiple Piezo-Patch Energy Harvesters on a Thin Plate With AC-DC Conversion

Piezo-patch energy harvesters can be readily attached to plate-like structures in automotive, marine, and aerospace applications, in order to exploit the broadband vibration of the host system. Power output investigations of such patch-based harvesters, when connected to practical interface circuits, require accurate models for harvesting performance evaluation and optimization. This paper proposes an analytical approach to derive the closed-form mechanical and electrical response expressions of the multiple piezo-patch energy harvesters (MPEHs) by integrating an equivalent load impedance, which consists of the harvesting circuit and the overall piezo-patch capacitance into a distributed-parameter model of the plate. Moreover, an equivalent circuit model of the electromechanical system is developed in a circuit simulator software SPICE for system-level simulations, taking into account the interconnection of piezo-patches and multiple vibration modes of the plate. Numerical SPICE simulations are then validated for the conventional ac input-ac output problem by the experiments and existing analytical solution. The proposed analytical model is validated by the experiments for the standard ac input-dc output problem. Finally, the analytical and numerical results for the peak power output of the MPEHs in series/parallel configuration with ac and dc interface circuits are presented, and shown to be in good agreement with the experimental results.