Improved Frozen Permeability Method Considering Load Condition Flux Path for Dual Stator Permanent Magnet Synchronous Motor

Urban air mobility (UAM) requires highly reliable propulsion systems, for which the dual stator permanent magnet synchronous motor (PMSM) is suitable owing to its structural redundancy. Accurate parameter estimation is essential for modeling such motors. This paper proposes a frozen permeability method (FPM) that maintains the magnetic flux path under load conditions to improve the accuracy of parameter estimation. In this method, the permanent magnet (PM) is retained as a magnetic source during flux linkage calculation, and its internal magnetization direction is considered. To verify the effectiveness of the proposed method, the conventional FPM, which treats the PM as air, was defined as a comparison reference. Simulation results confirmed that the proposed method reduces torque estimation errors by maintaining the correct flux path under load conditions. Experimental validation was also conducted, confirming the applicability of the proposed method under various current amplitudes and phase angle conditions. The proposed method contributes to improving parameter estimation accuracy for dual stator PMSM, which is expected to enhance the modeling accuracy of motor systems in high-precision control and digital twin-based applications.