Improved analytical accuracy for permanent magnet torque machines: Accounting for armature magnetic field effects on magnetic circuit saturation

High-Accuracy Analytical Model

The study, led by Xianguo Gui，takes into account multiple nonlinear factors in the process of motor performance calculation. The new analytical model incorporates both main and leakage magnetic flux paths and employs a unique iterative process incorporating main and leakage flux saturation factors. This allows for precise calculation of magnetic saturation in each part of the motor, directly addressing the inaccuracies of conventional approaches.

New Motor Design Method Cuts Cost and Development Time

Permanent Magnet Torque Machines (PMTMs) excel in high-torque applications but face a core challenge: their high operating current distorts the internal magnetic field, causing saturation in the iron core. Traditional analysis methods often neglect this saturation, leading to significant performance prediction errors. The team proposed a new nonlinear analytical method with high accuracy and strong practicality. The fundamental wave of the load air-gap flux density calculated by the new method showed an error of only 1.7% compared to FEM results, the gold standard for simulation. In contrast, the traditional linear analytical method had a 10.2% error.

This method is fast and conceptually clear, making it highly suitable for initial motor design and optimization. It allows engineers to predict motor performance more accurately before prototyping, reducing development time and cost.

Future outlook: Predicting Motor Performance Precisely

We plan to extend this analytical method to a broader range of specialized electrical machines, particularly other high-torque or high-current variants where magnetic saturation is a critical design challenge. This will validate the universality and robustness of the proposed modeling approach across different motor topologies and operating conditions.

Furthermore, our immediate goal is to develop this methodology into integrated, user-friendly software design tools. By embedding this accurate model into the initial design phase, we aim to significantly shorten development timelines for engineers, reduce prototyping costs, and accelerate the creation of next-generation, high-performance motor systems for industrial applications.

The complete study is accessible via DOI: 10.30941/CESTEMS.2025.00025