Modeling and Simulation of Vibrations' Energy Harvesting From Cars' Suspensions and Seats Using Equivalent Electrical Models

Abstract

This research work investigates the vibrations' energy harvesting from vehicles' suspension system and seats using piezoelectric stacks. For this purpose, a simple quarter car model is used to estimate the quantity of harvested voltage and power. The novelty of this work consists in utilizing a 5-DOF quarter car model to analyze the energy harvesting capabilities from both car's suspension system and seat. Also, based on the electromechanical analogy, the equivalent electrical circuit approach is used to implement the whole system, i.e., the suspension's system, the car's seat, the driver's body, and the associated piezoelectric harvesters in LTspice software. Moreover, different situations are studied for the harvesters' location, in order to investigate their effects on the system's dynamics and choose the optimal place ensuring both more comfort for the driver and the passengers and also to harvest a maximum of vibrations' energy. Simulations done in the frequency domain considering a sinusoidal excitation of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.5{{\ g}}$</tex> ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4.9{{\ m}}/{{\mathrm{s}}^2}$</tex> ) amplitude and a resistive load of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$30{{k\Omega }}$</tex> , indicated that, connecting a piezoelectric harvester in parallel with the suspension's elements allows harvesting maximum of RMS voltage ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$87.57{{\ V}}$</tex> ) and RMS power ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$255.6{{\ mW}}$</tex> ) but this connection changes the displacements of the cabin floor and the driver's body, i.e., it decreases the driver's and passengers' comfort. Also, the quantity of voltage and power harvested from the suspension's elements is more important than that collected from the seat. Finally, connecting piezoelectric harvesters simultaneously in series with the suspension's and seat's elements allows harvesting a non negligeable quantity of RMS voltage (12.29V) and RMS power ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3.15{{\ mW}}$</tex> ) with low effect on the driver's and passengers' comfort (small displacements' difference).