Design of WFSM Using Sizing Method Combining 2-D Equivalent Magnetic Circuit Considering Nonlinear Characteristics

This article proposes a novel sizing method of wound field synchronous motor (WFSM) using a 2-D equivalent magnetic circuit (2-D EMC) considering nonlinear characteristics. The conventional sizing method is an analytical method predicting motor performance using a proportional formula based on size-related variables of the motor, which are shape ratio (SR), torque per rotor volume (TRV), and torque density (TD). However, the accurate results cannot be obtained only from the proportional formula because the performance of the motor varies greatly depending on the magnetic saturation of the core. In particular, since the WFSM does not use a permanent magnet (PM) for the field, it is important to reflect the magnetic saturation of the field core. Therefore, in this article, a novel sizing method of WFSM based on the 2-D EMC, which is a numerical method used to fast and accurately calculate the performance of the motor considering the magnetic saturation of the core, is proposed. Using the proposed design method, it is possible to not only accurately predict the motor characteristics according to the size but also determine the motor size that satisfies the requirement performances. The validity of the proposed sizing process is verified through simulations and experiments.