Utfört vid Volvo Cars med handledning av Satish Narayanan Ramachandran och Joachim Härsjö
Examinator: Torbjörn Thiringer, Inst för elektroteknik
Opponenter: Isak Ernstig och David Olofsson
With the introduction of electric cars, the drivetrain setup has greatly changed compared to cars with combustion engines. Due to the changed setup, external forces are more likely to trigger oscillations in the drivetrain. However, due to the fast and accurate control that the electric machine provides it should be possible to, by means of control, limit these mechanical oscillations.
In this work the possibility to damp potentially harmful mechanical oscillations in an electric vehicle drivetrain, by measuring only the electric machine speed, has been investigated. A plant model was built from known vehicle dynamics and several methods for observing and actively controlling the mechanical drivetrain oscillations have been reviewed and evaluated through simulations in Simulink.
It has been shown that it is possible to actively damp oscillations in the drivetrain by using a recursive least squares algorithm in combination with different controllers, and by only measuring the EM speed. The robustness and performance of the developed concepts have been evaluated and the results indicate that it is possible to damp oscillations caused by external torque transients for a system with varying properties.