Selection of slot-pole combination of permanent magnet machines for aircraft actuation

This paper investigates the influence of the slot/pole (S/P) combination on inter-turn short circuit (SC) current in fault tolerant permanent magnet (FT-PM) machines. Eight different S/P combinations are studied. For the investigation, methods based both on 1D and 2D analytical models were adopted. The 2D analytical model is used in combination with genetic algorithm (GA) optimisation to design the FT-PM machine, then a 1D analysis is used to estimate the SC current. It is shown that S/P combination has a significant influence on inter-turn SC fault current and needs to be considered during the design to balance the performance and fault tolerant criteria of the application.