Permanent magnet synchronous machines (PMSM) are a key component of modern, highly efficient electric drives used in a wide variety of applications, ranging from electric vehicles to industrial automation. To achieve optimal motor control, particularly when employing Field Oriented Control (FOC), an accurate knowledge of the d-axis and q-axis inductances is crucial. Incorrect values of these parameters lead to reduced torque, decreased efficiency, and limited dynamic response. This master's thesis focuses on a comprehensive investigation of inductance determination for Interior Permanent Magnet (IPM) motors. The aim of the work is to critically analyse existing measurement methods, practically implement them on a selected motor, and compare the results with analytical and numerical calculations. Based on this extensive analysis, the most suitable method for inductance determination is selected. The introductory part of the thesis presents a detailed overview and critical analysis of both established and modern methods for two-axis inductance measurement. The reviewed literature is categorized according to the nature of the measurements into static methods (performed with a locked rotor), dynamic methods (requiring rotor rotation), and controller-based methods, where parameters are determined in real time from the motor's current responses using the implemented control algorithm. Special attention is also devoted to the impact of magnetic saturation and operating temperature on variations in inductance values. The practical part of the thesis involves the execution of the selected and most relevant methods on a specific IPM motor. This section includes a detailed description of the experimental setup, encompassing hardware and software, the execution of the tests, and a comprehensive presentation and analysis of the results. Particular emphasis is placed on a critical evaluation of all measured values, including an assessment of measurement uncertainty, a comparison of results across different methods, and a thorough analysis of the inductance's dependence on current (magnetic saturation). In parallel with the practical experiments, an analytical and numerical calculation of the motor inductances is carried out. First, a theoretical model is introduced, incorporating the geometric and material parameters of the selected motor along with the corresponding calculation equations. Subsequently, the numerical software tool Altair Flux is utilized for Finite Element Method (FEM) modelling, enabling precise determination of the magnetic field and inductances under realistic operating conditions. These theoretically and numerically derived values serve as a reference and are directly compared with the experimental measurements. In the final part of the thesis, a synthesis and evaluation are conducted based on the entire course of the research. Objective criteria are defined to assess individual methods, such as accuracy, execution time, equipment complexity, and robustness with respect to saturation. Taking these criteria, the experimental results, and the analytical model comparisons into account, the optimal method for inductance determination is thoroughly justified and selected. The final outcome of this work provides a systematic overview of methods, a dataset of experimentally measured and reference values for the selected motor, a critical comparison of approaches, and a concrete recommendation for the most reliable and efficient method in engineering practice.
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