Efficient Electromagnetic Analysis of a Wound Field Synchronous Generator with Complex 3D Stator Cooling Passages

Efficient electromagnetic analysis of a Wound Field Synchronous Generator (WFSG) with axially non-uniform cooling passages requires consideration of the passage geometry, whereas the high computational cost of full Three-Dimensional (3D) Finite Element Analysis (FEA) limits its applicability to iterative design. This paper proposes a segment-wise nonlinear two-dimensional (2D) FEA method. The cooling passage geometry is divided into representative axial segments according to changes in its cross-sectional geometry, and the overall flux linkage, electromagnetic torque, and core loss are reconstructed through axial-length-weighted aggregation of the segment-wise results. The proposed method is validated against full 3D FEA for a model including the cooling passages. The predicted induced voltage and torque characteristics show close agreement with the 3D FEA results. In addition, compared with conventional 2D FEA that neglects the cooling passages, the proposed method reduces the core loss discrepancy relative to full 3D FEA. The proposed method also substantially reduces computational cost, providing an effective balance between prediction accuracy and computational efficiency for the iterative generator design and optimization.