A Novel Modeling Method for No-Load Saturation Characteristics of Synchronous Machines Using Finite Element Analysis

To reduce the manufacturing costs while meeting product specifications, wound-field synchronous machines (WFSMs) must be designed using a finite element analysis (FEA) with improved accuracy. Various physical and mechanical factors affect the characteristics of WFSMs, preventing their accurate analysis. In this study, we determined the error factors of the analysis focusing on no-load saturation characteristics, which are the most fundamental characteristics of WFSMs. The comparison between measured and analyzed characteristics revealed that the analysis error is mainly governed by four factors: limitation in the measurement of the magnetic property, stacking factor of cores, degradation due to punching, and manufacturing tolerance of gap length. To incorporate the influence of these factors into the FEA, this article proposes a practical modeling method consisting of six parameters, which can be identified through the least squares method and a simple optimization. The analysis error was reduced to less than 2% by using the proposed modeling method from its initial maximum value of over 13%.