The influence of magnetic hysteresis on HF injection based inductance calculation

Saliency-based sensorless control relies on the position dependence of the high-frequency inductance, referring to the relation between the amplitudes of carrier voltage and current response. Deriving this relation even from nonlinear machine models yields different inductance values from the ones generally measured. The present paper aims at further clarifying this discrepancy by investigating the influence of magnetic hysteresis on the HF inductance. Experiments with a reluctance synchronous machine demonstrate that the hysteresis effect significantly increases the amplitude of the HF current response and, thus, lowers the measured inductance. While the injection amplitude has a direct impact on the inductance value, the frequency has an effect only beyond 1kHz. Furthermore, the influence of hysteresis on the HF inductance depends on the injection direction.