A Novel Strategy of DFIG in the Frequency Modulation for Power Grid

The DFIG uses a converter based on space vector pulse width modulation (SVPWM) to realize the decoupling of electromagnetic and mechanical power, but the DFIG cannot respond immediately when the power grid frequency fluctuates. In order to solve this problem, based on the existing model of the DFIG and its control methods, this paper proposes an additional frequency control link in the active power control of rotor side and make the DFIG's rotor release or absorb part of kinetic energy, which can change the active power output according to the change of the grid frequency, so as to realize the frequency control of wind turbines and increase the equivalent inertia of the power system. Simulation results demonstrate the effectiveness of the proposed method. The control strategy can make the wind farm of DFIGs participate in the frequency regulation of power system, and the regulation effect becomes better with the increase of wind power penetration rate.