Abstract:
In this current study, the validation and evaluation of a behavioral circuit model of electro-
static MEMS converters are presented. The main objective of such a model is to accurately find the
converter behavior through the proper choice of its circuit elements. In this regard, the model enables
the implementation of the electrostatic MEMS converter using commercially available off-shelf circuit
elements. Thus, the overall vibration energy harvesting system can be implemented and tested with-
out the need for fabricating the converter. As a result, the converter performance can be verified and
evaluated before its fabrication which saves the expenses of fabricating trailed prototypes. To test the
model, we apply it to an enhanced converter in which the conventional electrostatic MEMS converter
is modified by depositing the tantalum pentoxide, Ta2O5
, a high dielectric constant material, on its
fingers’ sidewalls. Such a deposition technique causes an appreciable increase in the overall converter
capacitance and, in turn, the output power, which is boosted from the range of µw to the range of
mW. Next, the converter behavioral circuit model, which is based on representing its capacitances
variations with respect to the input displacement, x caused by the vibration signal, C–x curve, is
built up. The model is qualitatively validated and quantitatively evaluated. The enhanced converter
performance is investigated through the interaction of its model with the power conditioning circuit.
From the simulation results, it is revealed that the converter behavioral circuit model accurately
accomplishes the vibration energy conversion operation. As a result, the specification of the required
controlling pulses for the converter operation is accurately determined. Finally, the model accuracy is
validated by calibrating its performance with a traditionally simulated and fabricated electrostatic
MEMS converter.
