Efficiency improvement of a high-speed permanent magnet excited synchronous machine by the use of spot-welding as lamination packaging technology

In this paper, an efficiency improvement of a high-speed permanent magnet excited synchronous machine (PMSM) by the use of spot-welding as lamination packaging technology is realized. Welding, interlocking, clinching and gluing are typical technologies to manufacture electrical steel stacks of electrical machines. However, these processes deteriorate the magnetic properties of the steel sheets, thereby decreasing the overall efficiency of the machine. Variations of line-welding (six, eight, twelve, thirty two and forty) line welds and spot-welding procedure is performed and analyzed. A semi-physical iron loss separation approach is used to extract the IEM iron loss model (Eggers et al., IEEE Transactions on Magnetics 48(11) (2012), 3021–3024). These parameters are utilized during the finite element simulation to calculate the effective iron loss (efficiency) of the machine while using each joining procedure. A low speed, high-speed and WLTC-c3 driving cycle is exemplarily used to analyze the effects of each procedure on the machine efficiency at the different operating conditions.