Power-Response-Equivalence-Based Dual-VSG Coordinated Control for Energy-Storage DFIG Wind Turbines Under Frequency-Support Operation

Variations in wind-turbine rotor speed and converter power margin under different operating conditions constrain the frequency-support power output of wind turbines, thereby affecting the controllability and stability of the frequency-support response. To address this problem, this paper proposes a dual virtual synchronous generator (VSG) coordinated control method for energy-storage doubly fed induction generator wind turbines based on frequency-support power-response equivalence. First, frequency-support power-response models are established for the VSGs implemented at the rotor-side converter and the grid-side converter to describe the active-power dynamic characteristics of the two frequency-support channels. Second, using the target inertial-support power response as the reference, the dual-VSG parameter configuration is transformed into a power-response consistency optimization problem. Furthermore, considering rotor speed, state of charge (SOC), and the grid-side converter upward power margin, the inertia-support and primary frequency regulation power contributions are assigned between the stator and grid-side converter channels. Hardware-in-the-loop validation results show that the proposed method coordinates the dual-channel frequency-support power output under four typical operating conditions with high/low wind speeds and high/low SOC levels, maintains a consistent frequency-support power response, and achieves controllable and stable frequency support over a wide operating range.