Active Differential Inductance Control of Permanent Magnet Synchronous Machines Using Short-Circuited Rotor Coils

In this paper, novel active strategies to influence the differential magnetic anisotropy in permanent magnet synchronous machines using short-circuited coils in the rotor to improve the self-sensing capabilities at low and zero speed including manufacturing solutions are presented. The critical range of low differential anisotropy can be shifted to higher loads or actively skipped. Alternatively, the inductance characteristics can be linearized over load. This enables machine designs with good performance in torque density and efficiency as well as good self-sensing characteristics without major compromises. The resulting inductance characteristics are simulated for nonlinear machine models of different rotor configurations.