Analyses of Power Output of Piezoelectric Energy-Harvesting Devices DirectlyConnected to a Load Resistor Using a Coupled Piezoelectric-Circuit FiniteElement Method

摘要

A coupled piezoelectric-circuit finite element model (CPC-FEM) is proposed forthe first time to study the power output of a vibration-based piezoelectricvibration-based piezoelectric energy harvesting devices (EHDs) that is directlyconnected to a resistive load. Special focus is given to the effect of theresistive load value on the vibrational amplitude of the piezoelectric EHDs, andthus on the current, voltage, and power generated by the EHDs. In theliterature, these outputs are widely assumed to be independent of the resistiveload value for the reduction in complexity of modelling and simulation. Thepresented CPC-FEM uses a cantilever with sandwich structure and a seismic massattached to the tip to study the following load characteristics of the EHD as aresult of changing the resistive load value: (1) the electric outputs of theEHD: current through and voltage across the resistive load, (2) the powerdissipated by the resistive load, (3) the vibration amplitude of tipdisplacement of the cantilever, and (4) the shift in resonant frequency of thecantilever. Investigation results shows significant dependences of the vibrationcharacteristics of the piezoelectric EHDs on the externally connected resistiveload are found, rather than independence as previously assumed in mostliterature. The CPC-FEM is capable of predicting the generated power output ofthe EHDs with different resistive load value while simultaneously calculatingthe effect of the resistive load value on the vibration amplitude. The CPC-FEMis invaluable for validating the performance of designed EHDs before fabricationand testing, thereby reducing the recurring costs associated with repeatfabrication and trials. In addition, the proposed CPC-FEM is potentially usefulin device designs optimisations for maximal power generation.