Modified AC standstill method for PMSM d-q axis inductances measurement

This study reports a modified AC standstill method (ACSM) for the d - q axis inductances measurement of permanent magnet synchronous motors (PMSMs), which is free of locked tooling. Based on the voltage function, the d - q axis inductances of a PMSM are derived from the ACSM under the two same phase (TSP) condition through the Laplace transform. The inductance values of the studied external rotor PMSM are measured by this reported TSP ACSM, which are also compared with the DC standstill and the previous ACSM tests. During the process of the TSP ACSM measurement, the voltage source inverter of the motor provides three phase excitation signals which can produce self-saturation and cross-saturation. The theoretical analysis and experimental measurement results validate the accuracy of this reported method.