Study on Location Detection of PMSM Rotor Based on Sliding Mode Observer

The Sliding Mode Observer(SMO) was formed by using the mathematical model of PMSM under the αβ coordinate according to the control theory of the sliding-mode variable structure, and the location of the rotor was detected by using the movement of the sliding mode and taking the deviation between the three-phase current estimated of the PMSM winding and the current measured as the switching surface of the sliding mode. The phase compensation was implemented by using the multi-linearity method in order to improve the detection precision of the location of the SMO rotor in allusion to the nonlinear phase delay of the counter electromotive force as a result of two levels of LPFs. Further, the simulation model for detection of the SMO rotor location of PMSM was set up, and the simulation result indicated that the detection error of the rotor location was controlled within 1.5% except the moment of startup, and the error of the rotor location was controlled within 4% when the change of resistance and the inductance of the winding was +/-20%.