Q-axis pulse based identification of the anisotropy displacement over load for surface mounted PMSM

This paper proposes a self commissioning test sequence to identify the load dependent anisotropy displacement without a position sensor. Strong q-axis voltage pulses that causes a macroscopic q-current response, will - in a saturating machine - also cause a slight parabolic d-axis current. The squared component in the d-current reveals the cross saturation information, which is used to derive the anisotropy displacement curve. In this way one key parameter for low speed sensorless control is identified in quasi standstill and without load.