Magnetic Characterization of Stator Segments Considering Mechanical Stress

The efficient design of high power density electrical machines suited for traction applications relies on accurate material models. For the stator and rotor steel lamination the models have to take the manufacturing influences into account. In this publication, a test bench for stator teeth is used to investigate the impact of mechanical stress on the magnetic properties. The main cause for the mechanical stress in the stator core is the shrink fitting process. Two electrical steel grades suited for high frequency and high power density applications are investigated. Depending on the operating point and the applied mechanical stress, the core losses of the setup increase about 25%. The introduced separation approach for stator tooth losses and magnetization curves allows the estimation of manufacturing influences for different material grades. This gives the opportunity to adapt core loss models to additional occurring losses due to the assembly of the machine parts.