An Upper Bound of the Torque Production for Round Rotor Wound Field Synchronous Machines and its Electromagnetic Scalability

Efforts have been made to accurately predict the torque production of AC machines. This paper derives an upper bound of the torque production and average shear stress for round rotor wound field synchronous machines (WFSMs). The result is written as a function of the machine's major geometries and excitation condition. The ratio of the actual value and the upper limit could be used as an indicator of how further the material capability is pushed, i.e. how well a machine is designed. The result is further investigated to discuss the electromagnetic scalability and the sizing law of round rotor WFSMs.