Measurement-Based Nonlinear Modeling of PMSMs

This article is about measurement-based modeling of PMSMs. Typically, these machine designs feature nonlinear characteristics regarding the stator phase currents and show rotor angle dependent behavior. Thus, non-sinusoidal linked fluxes as well as higher torque harmonics occur. As this cannot be represented by classical dq0-based theory, a feasible modeling strategy had do be established and its suitability is illustrated by analyzing a prototype in detail. Measurements are conducted on a test rig and a nonlinear machine model is derived. The measurement setup and the automatized measurement process are described and the obtained machine characteristics are analyzed. When compared with results based upon finite element (FE-) simulations, this allows for identifying manufacturing tolerances and deviations of the material characteristics compared to presumed behavior. Moreover, tolerances among the rotor pole pairs can be identified if the measurements are conducted for an entire rotor revolution. The suitability of the derived model is verified by determining ideal stator phase currents for a particular optimization task.