Active Damping Control of Torsional Vibration in a Diesel Hybrid Powertrain

This paper has designed a real time control algorithm to use ISG motor actively compensate the torque ripple produced by the engine, to reduce torsional vibration. This paper consists of 3 parts. In the first section, this paper has introduced the research object and its modification for experiments. Then the development of control strategy is presented. The engine dynamic model is built, and real-time control with a feedforward unit and a feedback unit is derived. Encoder and cylinder pressure is used for engine torque estimator. Then the ISG motor output the counter-waveform to make the overall output smooth. In order to verify the effectiveness of the control strategy, the final section has established a test bench, where two experiments are carried out. One of the experimental conditions is to set the engine at a constant operating point, while the other is to crank the engine from 0 rpm to idle speed with ISG motor. At constant operating point, speed fluctuation decreases by as much as 79.15%. In terms of vibration index, the vibration is decreased by 83%. During engine start, the engine speed profile is smoother. In terms of vibration index, the vibration is reduced to an extent of 49.9%. The active damping control proves effective by both experiments.