Magnetic Saturation Aids Flux-Weakening Control: Using Lookup Tables Based on a Static Method of Identification for Nonlinear Permanent-Magnet Synchronous Motors

For a given power voltage, the usual fluxweakening control of permanent-magnet synchronous motors (PMSMs) is based on two independent current regulators to expand the speed range of linear PMSMs. Therefore, the magnetic saturation is not often taken into account in these control strategies. Many authors have worked on this topic in recent years, but questions remain about the optimization of the flux-weakening space. In this article, by taking into account the magnetic saturation, an optimal flux-weakening control scheme has been developed. The proposed method is based on a lookup table that provides the current set points according to the speed and power voltage measurements. To implement this control strategy, two steps are required. The first presents a specific characterization scheme of PMSMs. The second shows how to build lookup tables for the flux-weakening control by using an optimization algorithm under constraints, based on obtained identification results. An example is given to illustrate each step of this study. Please be advised that the control scheme carried out in this article is under patent by Piaton et al.