Consideration of Mutual Torque in Sizing of Double Stator Wound-Field Flux Switching Machine for Heavy-Duty Traction Motors

The double stator wound field flux switching motor (DSWFFSM) has the potential to replace synchronous ho-mopolar and induction motors in mining trucks and other heavy-duty off-road traction applications. This is because DSWFFSMs possess high torque density, high efficiency and relatively simple structure suitable for operation in harsh environments. The sum of the individual toque contribution of the inner and the outer stators of the DSWFFSM is less than its total output torque, meaning that additional torque due to mutual interaction between inner and outer stators need to be accounted for in sizing of DSWFFSM. Therefore, in this study, the relationship between total and mutual torques is semi-analytically established and the percentage contribution of the mutual to total torque is found to be 8% approximately. By applying numerical regression technique, this mutual torque can be analytically computed into the sizing of the DSWFFSM. To this end, a 323 kW DSWFFSM is sized based on the proposed semi-analytical technique and then validated using finite element analysis (FEA) modelling and simulation. The FEA calculated electromagnetic results under no-load and rated load conditions confirm the accuracy of the proposed semi-analytical sizing procedure.