Induction Machine Modeling Approach Based on 3-D Magnetic Equivalent Circuit Framework

Developments in power electronics technology, materials, and changing application requirements are driving advances in electric machines. Limitations of standard motor design, particularly for induction machines, restrict performance capabilities in drive applications. Current computer-aided design tools are inadequate to overcome these limitations. Lumped-parameter and finite-element models have limited accuracy and heavy computational effort, respectively. Magnetic equivalent circuits (MEC) avoid these limitations. This paper presents an induction machine MEC model geared toward design and based on a 3-D MEC framework introduced in previous work. A matrix formulation suitable for computation is described. Details of mesh generation for the MEC approach are provided. Force and performance estimation are discussed. Simulations based on this approach are able to track dynamic effects, such as rotor slot torque ripple contributions. Comparisons are made to a 500 W purpose-built machine. Results from lumped-parameter and finite-element models and measurements indicate that MECs, corrected for local saturation, are a promising option for design tools.