To address the frequency security and stability issues caused by increasing wind power penetration

an inertial control method of doubly fed induction generators suitable for high wind power penetration and large power shortfall conditions is proposed based on revealing the shortcomings of tradition differential inertial control method

namely mode switching method. The inertial control mode is triggered by setting logic judgment conditions including frequency derivative and frequency deviation

and is blocked by setting rotor speed limit

thereby the operating mode switchover between maximum power point tracking (MPPT) and inertial response can be achieved autonomously. An additional constant electromagnetic torque is set in this method

and the inertial response intensity does not recede with decrease of rotor speed. The system frequency excursion can be inhibited more effectively using mode switching method instead of differential inertial control method within the stable operation constraint of wind turbine to mitigate frequency deviations. The effectiveness and superiority of mode switching method are validated by simulation results. This work is supported by National Natural Science Foundation of China (No. 51190104).