Analysis and Optimization of Current Coupling Control in Flux-Weakening Region of PMSM

Different from the independent control of
dq
-axis current (
i
$_{{ sd,q}}$
) in the base-speed region, the flux-weakening (FW) region requires coupling control of
i
$_{{ sd,q}}$
to satisfy the maximum voltage constraint. This article revealed the reasons for the failure of the rapid current coupling control in FW region from the perspectives of control structure and vector trajectory. The direct and indirect coupling model (DCM and ICM) are quantitatively calculated and compared. The ICM is proved to have higher accuracy than DCM, which is used to optimize the current following performance and suppress voltage fluctuation during transition process between maximum and nonmaximum torque condition. Finally, the comparative experiments verified the analysis-correctness and superiority of the proposed method.