Master–slave coordinated reactive power decoupling control strategy for cascading fault ride-through of doubly fed induction generators

Abstract

To address reactive power competition, high-frequency electromagnetic oscillations, and fault-energy propagation caused by active power backflow in doubly fed induction generators (DFIGs) under cascading faults, a master–slave coordinated fault ride-through strategy is proposed. First, a central-controller-led architecture decouples the generator’s excitation-related reactive power demand from the grid’s dynamic reactive power support demand. This enables the coordinated allocation of multi-source reactive power across the rotor-side converter (RSC), grid-side converter, and static var compensator. Second, an active damping mechanism is integrated into the referenced model predictive control (MPC) framework of the RSC to suppress high-frequency electromagnetic oscillations and rotor overcurrent during fault transitions. By incorporating the central controller’s excitation demand into this MPC optimization process, system-level decision-making and converter-level control are synergistically optimized. For the GSC, a dual-channel linear active disturbance rejection control structure is designed. The active power backflow is regarded as a generalized disturbance and compensated in real time, enhancing dc-link voltage stability and overall disturbance rejection. Finally, MATLAB/Simulink simulations verify that the proposed strategy effectively coordinates multi-source reactive power, suppresses electromagnetic oscillations and dc-link voltage fluctuations, and improves the DFIG fault ride-through and dynamic grid support performance under cascading faults.