Study On The Control Strategy Of Permanent Magnet Synchronous Motor With Insensitivity To Parameter Variance

With the advancement of technologies relating to PMSM drive systems,the motor efficiency and system performance have been enhanced significantly.Meanwhile,demands for PMSM drives with higher control accuracy are becoming more urgent.The PMSM model parameters are,however,vulnerable to varying degrees of variance,depending on the ambient and working conditions.Further developments and applications of PMSM drives are thus hindered.Present technologies as countermeasures,including parameter identification and active disturbance rejection control,cannot provide a perfect solution to this problem yet.Therefore,the control strategy with insensitivity to PMSM model parameters is a research area of significant value.The thesis is organized as follows:First,equivalent circuit and mathematical models of the Interior Permanent Magnet Motor are built based on its physical principle and analysis is performed in terms of the active power and the operating region with high efficiency of the motor.Then problems about the initial rotor position detection is described,followed by a detection method based on the proposed virtual dq reference frame.Theoretical analysis,simulation using MATLAB and experimental results are given to verify the feasibility and the advantage of this method.Next,the sliding mode extremum seeking algorithm is introduced and applied to the MTPA control of IPMSM.Both dynamic and static control performances of the algorithm are analyzed theoretically,subsequent simulation and experimental results are also presented to show the validity of the control algorithm from the practical perspective.Finally,a novel flux weakening control strategy based on the sliding mode regulator is proposed.With the voltage feedback control structure,the conventional PI regulator in the flux weakening loop is replaced by the sliding mode regulator.The principle and mathematical model of this regulator is described in detail,together with thorough analysis of the decoupling effect introduced by the regulator.Empirical results of flux weakening control based on the PI regulator and the sliding mode controller are compared and analyzed in terms of the control performance at last.As per the comparison results,the sliding mode regulator exhibits comparable feasibility and static performance to its PI counterpart while possessing better dynamic performance.