Experimental Estimation of Inductance for Interior Permanent Magnet Synchronous Machine Considering Temperature Distribution

This paper quantitatively analyzes inductance estimation errors due to temperature variation and proposes accurate experimental estimation methods considering the temperature distribution of an interior permanent magnet synchronous machine (IPMSM). Accurate knowledge of direct and quadrature-axis inductances is essential for high-performance control of an IPMSM. From the quantitative error analysis results, it is shown that the temperature variation is a very sensitive factor for the accuracy of the experimental estimation of the inductances. For accurate temperature consideration, two experimental estimation approaches are proposed. One uses the temperature measured at end windings to represent the internal temperature of the machine. The other uses both the measured temperature and other temperature information obtained from a temperature distribution analysis. This paper carries out a case study in which the proposed estimation methods are applied to a sample IPMSM with ferrite magnets. Experimental results are compared with finite element analysis (FEA) results in order to verify the effectiveness of the proposed methods.