With the increase of wind power penetration rate

the response ability of doubly-fed wind turbines to grid frequency gradually weakens

which has a huge impact on the frequency stability of the system.The independent frequency regulation capability of the doubly-fed wind turbines is currently insufficient to meet the frequency deviation requirements of the system

and it will result in high wind power permeability and low energy utilization rate.Therefore

energy storage equipment will be installed on the grid side of the doubly-fed wind turbines to form a wind storage joint system to participate in the primary frequency regulation of the system.In the article

a variable coefficient wind storage joint system based on the rotor speed and state of charge （SOC）is proposed to participate in the primary frequency regulation control strategy by utilizing the rotor kinetic energy of the wind turbine and the output of the energy storage equipment to jointly undertake the primary frequency regulation power demand.The doubly-fed wind turbine responds to the virtual inertia link by releasing or absorbing its own rotor kinetic energy

and dynamically adjusts the virtual inertia coefficient through its own rotor speed

andthe energy storage device dynamically adjusts the virtual droop coefficient based on its own state of charge to participate in the frequency response droop process.Finally

by building a simulation model to compare the frequency modulation effects of variable coefficient method

fixed coefficient method

and wind power independent frequency modulation under step load disturbance and continuous load disturbance

it is verified that the control strategy in the article can effectively reduce system frequency deviation.At the same time

the doubly-fed wind turbine can fully utilize its inherent rotor kinetic energy

and the energy storage equipment can also output smoothly

alleviating its overcharging and discharging problems

andimprove its service life.