Modeling and analysis of proximity losses in high-speed surface permanent magnet machines with concentrated windings

Surface permanent magnet (SPM) machines can be designed with fractional slot-concentrated windings (FSCW) to achieve extended speed ranges. High-speed operation can lead to significant levels of proximity losses in the stator windings due to substantial spatial harmonic magnetic fields in the air-gap as well as the high-frequency currents themselves. An integrated analysis tool is presented in this paper to calculate the strand- and bundle-level proximity losses in slotted stator conductors without requiring finite element analysis. A combination of analysis techniques, including Laplace equation solutions and conformal mapping, is used to estimate the magnetic field in each stator slot, providing the basis for proximity loss estimation. The match between losses estimated using the analytical model and finite element analysis is very promising.