Comparison of inductance determination methods of PMSMs for EV application

In order to design and control a permanent magnet synchronous machine (PMSM) for superior performance over a wide speed range, comprehensive testing methods with accurate measurements are of paramount importance. Moreover, in order to extract the maximum operating capability of the machine with inverter and magnetic saturation, accurate determination of dq-axis inductances over a wide speed range is essential. In this paper, a comparative analysis of three inductance determination methods based on stand-still and moving conditions of the machine is performed. The chosen test methods for measurement and calculation of d- and q-axis inductances are validated experimentally using a laboratory interior permanent magnet synchronous machine (IPMSM) prototype. Merits and demerits of these methods are thereafter analyzed comprehensively in terms of complexity of the methodology implemented, accuracy of parameters determined taking into account effects due to harmonics and temperature, scope and applicability of each of the test methods.