Nonlinear Magnetic Field Vector Control With Dynamic-Variant Parameters for High-Power Electrically Excited Synchronous Motor

Identifying the air-gap flux is a prerequisite for realizing the decoupling control between the air-gap flux and torque in an electrically excited synchronous motor (EESM) vector control system. For the nonlinear problem of EESM, the frequency response function method is introduced to analyze the air-gap flux voltage and current models' sensitivity to the motor parameters in this article. A dynamic air-gap current model for EESM based on the equivalent reaction inductance is proposed to solve the parameter dynamic-variant problem caused by the nonlinear magnetic distribution of the EESM. Meanwhile, the comparative analysis of effectiveness caused by linear and nonlinear flux identification errors in the hybrid air-gap flux model of vector control system is carried out. The effectiveness of the nonlinear dynamic model has been verified by simulation and experimental results, which shows its excellent control performance.