Comparison of Anisotropy Signals for Sensorless Control of Star-Connected PMSMs

Abstract

Estimation methods based on the magnetic anisotropy of the machine can be used to estimate the rotor position down to low speeds including standstill. Beside the classical approach of measuring current changes, anisotropy information can also be obtained by measuring the neutral point voltage when the machine is star-connected. This work analytically compares the anisotropy information that can be obtained by these two measurement approaches. FEM simulation results are also used to show the obtainable signals and the estimated positions for an exemplary PMSM.