Research on Proper Fractional-Slot Concentrated Winding Characteristics for A High Thrust Force Ultra-Low Speed Tubular PM Linear Machine

In this paper, the proper fractional-slot concentrated winding characteristics of a tubular permanent magnet linear machine (TPMLM) for the ultra-low speed direct application are investigated, which aims to improve the machine performances. Firstly, the thrust force of the machine with the design objectives is derived, which is closely related to the fractional values and magnetic source of the motor. Then the effects of different fractional value and magnetic source topologies on the thrust force characteristics are investigated and compared. Finally, the analysis results show that the lower fractional value with 120-slot-140-pole can offer high thrust force and power factor.