Engine Vibration Reduction Control in HEV Using Average Periodic Delay Repetitive Controller

This article proposes an engine vibration reduction control in hybrid electric vehicles (HEVs). The proposed method consists of a torque reference generator and an average periodic delay repetitive controller (APDRC). The torque reference generator produces a compensatory torque command synchronized with the phase of the flywheel in the internal combustion engine (ICE) using simple control rules and harmonic torque equations. The APDRC achieves high-accuracy current control of the electric motor connected to the ICE to track the torque command containing the fundamental and harmonic components. The proposed method does not rely on any estimator or mechanical model of the HEV powertrain so that it can be universally applied to mass-produced vehicles that adopt the same ICE and electric motor. The experimental results conducted on a 48 V mild HEV (MHEV) demonstrate that the proposed method significantly enhances riding comfort by reducing steering wheel vibration by up to 38% at 850 r/min during idling and by up to 49.8% at 1500 r/min during low-speed driving conditions.