Citation:
Meiling Zhu, Emma Worthington and James Njuguna. Coupled piezoelectric-circuit FEA to study influence of a resistive load on
power output of piezoelectric energy devices. Proceedings of SPIE Smart Sensors, Actuators, and MEMS IV. 4-6 May 2009, Dresden, Germany. Volume 7362, 736202. Ed. Ulrich Schmid
Abstract:
This paper presents, for the first time, a coupled piezoelectric-circuit finite
element model (CPC-FEM) to analyze the power output of vibration-based
piezoelectric energy harvesting devices (EHDs) when connected to a resistive
load. Special focus is given to the effect of the resistive load value on the
vibrational amplitude of the piezoelectric EHDs, and thus on the current,
voltage, and power generated by the EHDs, which are normally assumed to be
independent of the resistive load in order to reduce the complexity of modelling
and simulation. The CPC-FEM presented uses a cantilever with the sandwich
structure and a seismic mass attached to the tip to study the following load
characteristics of the EHD as a result of changing the load resistor value: (1)
the electric outputs of the EHD: current and voltage, (2) the power dissipated
by the resistive load, (3) the vibration amplitude of tip displacement, and (4)
the shift in resonant frequency of the cantilever. Significant dependences of
the characteristics of the piezoelectric EHDs on the externally connected
resistive load are found, rather than independency, as previously assumed in
most literature. The CPC-FEM is capable of predicting the generated power output
with different resistive load values while simultaneously considering the effect
of the resistor value on the vibration amplitude. The CPC-FEM is invaluable for
validating the performance of a device before fabrication and testing, thereby
reducing the recurring costs associated with repeat fabrication and trials, and
also for optimizing device design for maximal power-output generation.
