Influence of electric drive systems and their control on the NVH behavior of hybrid and electric vehicles - (PPT)

摘要

A good NVH performance is crucial for the market penetration of hybrid and electric vehicles. In conventional vehicles, the "mechanisms" regarding NVH are known sufficiently. The electric drive used in hybrid and electric vehicles, adds a new high dynamic torque source which also can affect the NVH performance leading to vibrations during start-up or during load changes. Thus, the electric drive is a further source of possible vibrational excitations in hybrid and electric vehicles and therefore cannot be neglected in the optimization process of the NVH behavior. Finally the electric drive also acts as superimposed disturbance source for mechanical vibrations in the drive train. Electric drives require an electrical supply with variable amplitude and frequency. Due to the harmonic characteristics of the electric machine and the used control with variable frequency, a torque ripple at the shaft of the electric machine results by physics. Especially the control of the electric machine in combination with its technology and topology has significant influence on the NVH behavior of hybrid and electric vehicles. Furthermore, deviations of sensor signals used as control reference of those variable frequencies and amplitudes play an important role regarding erroneous torque ripple at the shaft of the electric machine. In this article, these physical relationships are explained in detail and interpreted by means of practical examples and real measurements. Some solutions and remedial actions are shown to existing electrical drives and new approaches to improve the NVH performance using compensation algorithms and adaptive control methods are introduced.