Identification of steady-state inductances of PMSM using polynomial representations of the flux surfaces

Sophisticated model based control strategies for permanent magnet synchronous machines (PMSM) require precise modeling and knowledge of the machine parameters to achieve a high performance drive control. Nonlinear material characteristics of the iron and permanent magnets used in the machine lead to time-variant modeling approaches to deal with those phenomena. Typically iron losses are not considered in control plant modeling. However, it has already been shown that iron losses and non-ideal characteristics of the power electronic converter can be a major source of deterioration for the steady-state PMSM parameter identification. In this paper an elegant two-step identification strategy is proposed which minimizes the impact of iron losses and compensates for the influence of converter voltage errors during the identification of the flux surfaces (first step). In the second step the steady-state inductances are identified using polynomial representations of the flux surfaces. Like this, in contrast to conventional methods, the inductances can be identified even for zero current.