Cooperative Control Strategy of Load Shedding and Frequency Modulation of Doubly-fed Induction Generator considering Speed Recovery

With the deepening of the peak carbon dioxide emissions and carbon neutrality, renewable energy has become a strategic requirement. As a typical example, wind power generation accounts for an increasing share of the power system. When DFIGs adopt additional inertial control, the rotor speed may not be restored, which eventually causes the fan to deviate from the optimal operating point. Therefore, this paper proposes an additional inertial speed recovery strategy for DFIGs. First, additional inertial control is applied to the DFIG. It sequentially exits the additional inertial control and switches to the rotor speed recovery mode. The additional inertial tasks are distributed by the rest of the fans according to the amount of kinetic energy. In response to the problem of insufficient fan support capacity when the system fails, a cooperative control strategy for DFIG load reduction and frequency modulation is proposed, adjusts the pitch angle in real time, and calculates the wind energy utilization coefficient by comparing it given by sagging control. Finally, it is verified through simulation that the control strategy can reduce the magnitude of system frequency fluctuations and the level of frequency drop after failure, so as to effectively participate in system frequency modulation.