Current Response Based Online Inductance Estimation Method for IPMSM DTC Drives Considering Magnetic Saturation

In the direct torque control (DTC) of Interior Permanent-Magnet Synchronous Machine (IPMSM), the machine inductances are used to compute electromagnetic torque and stator flux. However, the inductances of machine vary nonlinearly with respect to the current due to magnetic saturation effect. To online estimate the inductances of an IPMSM, this paper proposes a novel method based on the current response caused by active voltage vectors inherent in DTC. There is no need to introduce other current injection signal. In addition, other machine parameters, such as winding resistance and rotor flux, are not required to online estimate machine inductance. The influence of magnetic saturation on the performance of the inductance estimator is also investigated. Simulation results verify the effectiveness of the proposed geometrical method in online estimation of inductance when taking magnetic saturation effect into account.