A Methodology for Inductance Measurement and Uncertainty Propagation in Synchronous Motors Under Magnetic Saturation Effects

This article proposes a reliable measurement methodology for high-efficiency line-start synchronous reluctance motors (LS-SynRMs), focusing on the measurement and analysis of phase inductance across various rotor positions and different supplied current values. The proposed method is valid for synchronous machines (SMs), and the LS-SynRM is used as an example of its verification. The investigation is motivated by the increasing demand for improved performance and efficiency in electromechanical systems, particularly in applications where the operating characteristics of a motor can be improved by proper control adjustment based on the actual motor inductance. Also, the actual accurate measured inductace of a newly developed motor can be used as a feedback for further motor design optimization. To address this, a novel methodology is introduced for evaluating the inductance based on flux linkage measurements. This approach incorporates a comprehensive uncertainty analysis, which enhances the reliability and accuracy of the results by accounting for various sources of measurement error. Experimental investigations were conducted to assess the inductance behavior of the LS-SynRM under different current levels. The results reveal significant effects of magnetic saturation on inductance variation, with measurements indicating a notable range of inductance values. Each measurement is accompanied by associated uncertainties, providing a deeper understanding of how inductance fluctuates with rotor position and current levels. By highlighting the relationship between inductance, rotor position, and measurement uncertainty, this research contributes valuable insights that can inform the design and optimization of future motor systems.