Study On Optimal Control Strategy Of Doubly-Fed Wind Turbine In Primary Frequency Modulation

With the continuous increase of the grid-connected capacity of wind turbines,the new energy power generation system puts forward higher requirements for wind power to participate in frequency regulation.However,the conventional doubly-fed wind turbine control is difficult to meet the frequency requirements of the system,and there are problems such as lack of inertial support for the grid frequency and weak primary frequency modulation ability.Therefore,a new study on the optimization and coordination control of primary frequency modulation of wind turbine is carried out.This paper introduces the model of doubly-fed wind turbine(DFIG),analyzes the characteristics of different frequency modulation control strategies of wind turbines,and sets up the mathematical models of DFIG at the side of the machine and the side of the grid.Based on the study of DFIG’s own load reduction standby,a primary frequency modulation control strategy based on the optimization and coordination of overspeed and variable pitch angle was proposed to adapt to the full wind speed condition.Secondly,in order to better improve the wind power frequency modulation ability,this paper proposes the wind storage coordination primary frequency modulation adaptive optimization control strategy considering the high permeability of wind turbines.Under the influence of quantitative analysis of permeability of new energy,the adaptive optimization control of primary frequency modulation of wind storage coordination is carried out according to different stages of frequency response,aiming at the frequency variation characteristics caused by load disturbance.Among them,the optimization control characteristics and parameter selection rules are analyzed,and two virtual power compensation strategies are added.The feasibility of wind storage coordination control strategy is analyzed,and the control effect is verified in the simulation.At the same time,starting from the coordinated control of energy storage and pitch Angle,a constant output state of primary frequency modulation is obtained,which can maximize the economic benefit of frequency modulation while satisfying the demand of frequency modulation.Finally,the simulation and experiment platform are built to verify the effectiveness of the proposed primary frequency modulation control strategy for doubly fed wind turbine.