Online parameter estimation of PMSM

The benefit of making an online parameter estimation of the PMSM is quite significant. In this method, regardless of the reasons for the parameter changes, the parameters of the motor are estimated correctly. This method instantly predicts saturation or temperature-dependent changing parameters that are not present in an off-line method. Thus, the control algorithm used by the method increases the efficiency of the motor drive to ensure better performance in terms of speed range or dynamic response. In this study, the online parameter estimation of the permanent magnet synchronous motor was studied considering the magnetic saturation. Current injection method was used to estimate the parameters including winding resistance, dq rotational inductance and rotor flow. During current injection, the inductances may change due to magnetic saturation. Neglecting these changes can cause faults especially in inductances. In this study, simplified equations were used to model the effects of self and opposite inductance saturation during the current injection. By incorporating this saturation model into the PMSM steady-state equations, the dq axis inductance, which varies with magnetic saturation and rotor flow, is correctly estimated. In addition, the estimate of the winding resistance is independent of other parameters and is not affected by magnetic saturation. In this method, the resistance values ​​varying depending on the temperature are estimated instantaneously by the current injection.