Active Torque Ripple Damping in Direct Drive Range Extender Applications: A Comparison and an Original Proposal

The conventional internal combustion engine (ICE) produces an inherent oscillating torque which causes a significant amount of vibration and noise and also reduces the power train life time. An opportunity for ICE used as range extender is to reduce the speed pulsation by using the electric machine (EM) for active damping of the torque ripple by applying an inverse torque sequence to crankshaft. This paper presents three different solutions for torque damping control system, i.e. a conventional proportional integral controller, an observer-based torque feed-forward technique and an original approach based on an adaptive multi-resonant controller. In order to better understand the torque engine oscillation phenomena an effective ICE model has been implemented aiming at comparing the effectiveness of the different techniques by simulation analysis. Experimental investigations are based on a dedicated laboratory test bench composed by an actual ICE connected to the EM. Obtained results show that a appreciable reduction of speed ripple and noise is achieved with the proposed active damping technique.