Design of salient pole PM synchronous machines for a vehicle traction application – Analysis and

摘要

This doctoral thesis presents a study on the development of a liquid-cooled frame salient polepermanent-magnet-exited traction machine for a four-wheel-driven electric car. The emphasis ofthe thesis is put on a radial flux machine design in order to achieve a light-weight machinestructure for traction applications. The design features combine electromagnetic and thermaldesign methods, because traction machine operation does not have a strict operating point.Arbitrary load cycles and the flexible supply require special attention in the design process.It is shown that accurate modelling of the machine magnetic state is essential for high-performanceoperation. The saturation effect related to the cross-saturation has to be taken carefully intoaccount in order to achieve the desired operation.Two prototype machines have been designed and built for testing: one totally enclosed machinewith a special magnet module pole arrangement and another through-ventilated machine with amore traditional embedded magnet structure. Both structures are built with magnetically salientstructures in order to increase the torque production capability with the reluctance torquecomponent. Both machine structures show potential for traction usage. However, the traditionalembedded magnet design turns out to be mechanically the more secure one of these two machineoptions.