An improved AC standstill method for inductance measurement of interior permanent magnet synchronous motors

An improved AC standstill method for inductance measurement of interior permanent magnet synchronous motors (IPMSM) is proposed in this paper. Only the single phase current source, oscilloscope and wattmeter are required in this method. The two single phase currents passing through the test circuit are proportional to d- and q- axes currents at operating condition respectively. Therefore the saturation and cross-coupling effect on synchronous inductances are included and the degree of influence of the cross-coupling effect on the inductances can also be evaluated. Finally, the relative deviation of the d- and q-axes inductances due to rotor positioning error which is the main error source is studied. This paper will introduce the principle equations and the result comparison.