Research On Control Strategy Of Wind Power System Based On Model Predictive Control

For a wind power system that includes wind turbines and traditional synchronous generators,frequency stability is a key indicator,which is usually supported by synchronous generators.However,as the penetration rate of wind turbines is getting higher and higher,the overall inertia of the system is getting lower and lower,and the limited synchronous generators cannot provide the required active power for frequency adjustment.This urgently requires wind turbines to participate in frequency adjustment.This paper takes the full-power permanent magnet synchronous generator and the wind farm as the research objects,and proposes optimized model predictive control strategies at the unit level and the electric field level,respectively.This paper establishes a model predictive control strategy to improve the system frequency difference and permanent magnet system output at the generator level,and proposes a permanent magnet synchronous generator designed based on model prediction to control the unbalanced power output caused by load switching and wind speed changes,to improve the problem of frequency vibration exceeding the safety critical value.This paper establishes an optimized predictive frequency adjustment model with frequency change rate and torque limit as constraints,system frequency difference and permanent magnet system output as optimization goals,and output torque increment that can improve the frequency dynamic characteristics of the power grid,and use it on the output adjustment of permanent magnet synchronous generator.The closed-loop system analysis is performed with Lyapunov stability,which proves the convergence and stability of the controller.Simulations are carried out under constant wind speed and variable wind speed under load mutation conditions to verify the effectiveness of the proposed algorithm.At the wind farm level,a multi-objective model predictive control strategy is designed to improve power tracking performance,reduce wind turbine load and system frequency difference,and study the weighing method of weight coefficients.Simulations under different wind speeds,different weight coefficients,and different permeability verify the effectiveness of the proposed method when the frequency fluctuates.