Field-Circuit Coupling Analytical Model for Doubly-Fed Induction Generator-Motor Under Variable Operating Conditions in Pumped Storage Units

In practical wide-slip-range applications, the electromagnetic performance (EMP) analysis of large-scale doubly-fed induction generator-motors (DFIGMs) faces a tradeoff between precision and computational speed. This article proposes a high-precision and efficient field-circuit coupled model (FCCM). The traditional ferromagnetic boundary and slip-dependent coupling are enhanced by iterative calculations between the subdomain and magnetic-electrical circuit models. Furthermore, a two-dimensional eddy current governing equation is developed for deep-slot and bar structures. This equation quantifies the skin effect’s nonlinear impact on winding impedance and enhances parameter calculation accuracy. Therefore, the FCCM achieves precise predictions of torque, voltage, and efficiency while maintaining high computational efficiency. Based on the FCCM, the variations in EMP of large-scale DFIGMs under sub/super-synchronous conditions are analyzed. Finally, multicondition experiments are conducted on a 10 MW DFIGM to verify the validity of the FCCM. This article provides a tool for multioperational EMP prediction and optimization of large-scale DFIGMs.