Dynamic Stability Analysis And Security Threshold Of Doubly-Fed Wind Turbine

In recent years,renewable energy,led by wind energy,has been developing rapidly.Its cleanliness and recyclability have made people's attention and utilization of renewable energy more and more urgent,and further promoted the development of wind power.However,due to the instability and intermittence of the wind and the impact of various uncertain loads and vibration loads,the main control system of WTGs is confronted with a nonlinear time-varying system,and its control strategy and mechanical structure are more and more complex.How to ensure the unit safe operation and the design life is becoming more difficult in high altitude and high salinity of the complex environment,the WTGs can determine the safe operation of the unit safety and stability,so for the parameters of the safety system safety threshold for further exploration.The main contents of this paper are as follows.Firstly,establish the transmission chain system(including pitch),tower,wind speed model,analysis of the establishment state space equation of wind turbine,and analyze the factors affecting the stability of the safety principle of wind turbine,calculation method of extreme load extrapolation,get wind turbine safe operation theory.Secondly,introduce the Lyapunov stability theorem and the theory and construction of V function,the content and design method of WTGs safety threshold and the square sum theory.Focus on construction the safety thresholds of tower system and transmission chain system.By means of system state space model,combining Lyapunov function and limit load The security threshold stability boundary and the security boundary are obtained by the square sum theory.Finally,take the actual test data of 1.5MW offshore wind turbine of a wind farm as an example,the security threshold of the model was determined by GH-Bladed and Matlab software.By analyzing the actual data,calculating and fitting the Weibull distribution data,using the statistical principle,calculate the actual operation of the cabin under the conditions of wind speed extreme displacement.By extrapolation and calculation of the limit load,the relevant boundary of the safety threshold of the WTGs is obtained and validated with the actual data.And the simulation of normal power generation and emergency shutdown conditions unit data,and actual data comparison,and verify the correctness of the safety threshold.