Influence of yoke and tooth saturation on the air gap field in Induction Machines: A new analytical approach

Saturation effects in the magnetic active iron areas lead to odd air gap harmonics in electrical machines. Whereas the influence of tooth saturation is analytical described by a flattening factor, the impact of yoke saturation is neglected by this factor so far. Finite element analyses are done in order to receive the air gap harmonics. The simulations are performed with high permeability material in the teeth and electrical sheets with real properties in the yokes and vice versa. This is done in order to separate both effects. Afterwards the air gap field of the sample Induction Machines is simulated including saturation effects in all magnetic active iron parts. The numerical simulations are compared with analytical approaches. In order to consider yoke saturation a new analytical approach is developed and validated.