Virtual Inertia Control Of Wind Turbines Considering Wind Speed Changes

Due to the randomness and intermittent nature of the wind speed,the output power of the wind turbine will have large fluctuations,which will affect the stability of the power system frequency,In addition,the grid-connected mode of converter further reduces the inertia of power system.In the case of large-scale wind power integration,giving full play to the power support capability of wind power is of great significance to alleviate the frequency regulation of conventional units and enhance the stability of system frequency.The existing research mainly uses the dynamic energy of the large moment of inertia wind wheel to provide active power support,but ignores the influence of wind speed change on the wind turbine operating stability and frequency modulation effect.Aiming at this problem,this paper takes virtual inertial control as the main research object,discusses the problems existing in the traditional fixed virtual inertia coefficient setting under changing wind conditions,and propose a virtual inertia coefficient setting method considering the wind speed variation.The main results are as follows:(1)It is found that the fixed virtual inertia coefficient under variable wind conditions causes wind turbine to be unstable or poor frequency modulation effect.When the wind turbine participates in the power grid frequency modulation,its stability and frequency modulation effect are affected by the maximum releasable kinetic energy and the actual releasable kinetic energy.Based on the analysis,the virtual inertia coefficient affects the amount of actual kinetic energy released,and the wind condition determines the maximum amount of kinetic energy released value.When the virtual inertia coefficient is fixed,the excessive release of kinetic energy will cause the wind turbine to be unstable,on the contrary,the frequency modulation effect is poor due to insufficient release of kinetic energy.(2)Fuzzy variable parameter virtual inertia control considering wind conditions.A virtual inertia coefficient setting method based on fuzzy controller is proposed.Based on the influence law for wind speed and virtual inertia coefficient on frequency regulation of wind turbine,the dynamic setting of virtual inertia coefficient under different wind speed is realized by using fuzzy algorithm,which sets larger virtual inertia coefficient under high wind speed and smaller one when wind speed is low.The specific performance is the stable operation of the wind turbine at low wind speed and sufficient active power support under high wind speed.Experiments based on an experimental platform for electromechanical dynamic simulation of power systems with wind power show that: compared with the traditional fixed-coefficient virtual inertia control,the fuzzy variable parameter virtual inertial control considering the change of the wind condition can balance the stability and frequency modulation effect of wind turbines under different wind speeds.