Vibration control of a P1 mild hybrid powertrain

Abstract

In hybrid powertrains, the engine excitation induces the vibration issues especially during transients of engine turning on and off as well as steady operating cases with high engine load in low rpm. In this paper, we design an integrated active flywheel with 48V motor to replace alternator and starter and suggest to cancel out the engine rolling as well as the torsional vibration. The phase based repetitive control law has been employed to control over the higher engine orders in addition to its ease of implementation. First, it is shown in the firing engine bench that both the torsional vibration and the rolling excitation of engine has been simultaneously reduced with a small fraction of total power consumption. With the combination of the 48V power systems and small modifications, the developed system has been implemented using a mass produced belt type Mild HEV vehicle and proved to operate successfully in terms of vibration control as well as the Mild HEV functioning.