Requirements on electric traction drives for road vehicles concerning power density, efficiency, noise emission and reliability are continuously increasing. At the same time the interaction between the electric converter and the electric machine becomes more important. The feeding of electric machines by modern power converters also causes some parasitic phenomena which work against the previously mentioned goals. These effects are basically torque pulsations, magnetically generated noise and vibrations, converter-caused additional losses and capacitive high-frequency currents in the bearings. Some of these effects can have such a negative impact on the highly utilised traction drive that they cause a fatal damage of the electric machine in the worst case. In this paper several reasons for the mentioned effects are described and analysed. The roots of the effects become more visible by the use of modern calculation and measuring methods. The parasitic effects and their consequences are illustrated by examples from different applications in traction drives. Primary and secondary actions to prevent from these parasitic effects are presented. Also the technical consequences of these measures are mentioned.
展开▼
