The invention discloses an inertial frequency-modulation drive rotating speed protection 
control system and method for a doubly-fed wind 
turbine. A 
wind speed detection module collects the 
wind speed, the rotating speed of a fan and the 
pitch angle parameter. According to a rotating speed protection control link, the real-time captured mechanical 
wind power of the fan is computed according to information collected by the 
wind speed detection module, and a loss computing module is connected with the rotating speed protection control link, the loss is subtracted from the real-time captured mechanical 
wind power; and the obtained computing result is compared with 
electromagnetic power output by a generator, an input and output 
power difference caused when the doubly-fed wind 
turbine participates in 
system frequency modulation is obtained, the input and output 
power difference is transmitted to a proportional link and an integration link through a trigger switch, the 
negative feedback power control quantity is output after the proportional link and the integration link act, and the 
negative feedback control quantity and an inertial frequency-modulation 
control signal jointly serve as a 
frequency modulation additional active power given value. By means of the inertial frequency-modulation drive rotating speed protection 
control system and method, secondary 
impact on the 
system frequency when the doubly-fed wind 
turbine exits from the 
frequency modulation can be avoided, and the problem that the 
power loss is large due to that fact that the rotating speed in the constant rotating speed region is overly lowered is solved.