Saliency based self-sensing enhanced operating condition monitoring using high-frequency injection under intentional magnetic saturation

In this paper, a simple technique to monitor the saturation effect on dq-incremental inductance is proposed. The high frequency injection (HFI) based technique can detect enhanced or diminished self-sensing ability under intentional magnetic saturation. Inductive saliency based self-sensing depend on the difference between d-axis and q-axis incremental inductance of the machine where the dq-axes inductive saliency is operating point dependent property. Prior researches showed the machine non-linear characteristic consideration under magnetic saturation is one of the key factors for successful self-sensing control. Incremental dq-inductance variations under flux-weakening and flux-intensifying operation are estimated. A system level self-sensing ability can be achieved since the incremental dq-inductance are estimated in the exactly the same HFI based self-sensing environment, i.e., the inverter, the current sensor resolution, the demodulation technique for differential carrier current, and the injected carrier frequency and amplitude.