Methods to Reduce the Errors in the d- and q-Inductance Estimation of a SynRM by Considering the Residual Magnetism

When the current dependent direct and quadrature inductances of a synchronous reluctance machine are calculated using measurement results, the estimated inductance values can drastically deviate from the actual ones for small current values. This paper presents an investigation of these deviations and introduces two methods to minimize the estimation errors, which consider the effects of the residual magnetism. Experimental results are also presented for a 12 kW reluctance machine.