Modeling And Control Of Wind Turbine Hydraulic Motor Pitch System

With the improvement of people’s awareness of environmental protection and the increasing sense of energy crisis,countries around the world have successively formulated a series of renewable energy development plans.Because wind energy has the advantages of low pollution,low mining cost and easy maintenance,it has become the primary choice of renewable energy.The importance that countries in the world attach to wind energy development not only promotes the development of the wind power industry,but also promotes the progress of wind power generation technology.At present,the installed capacity of wind turbines tends to be larger,and its control technology has developed from the original fixed-pitch control to the current variable-pitch control.The pitch operation of large-scale wind turbines requires the pitch control system to have the characteristics of fast response speed,high reliability,and easy implementation of large inertia loads.Because the hydraulic motor variable pitch control technology can well meet the requirements of large wind turbines,it has become one of the main choices of modern large wind turbines.However,the hydraulic motor pitch system is a complex nonlinear system with high-order multi-coupling,uncertain parameters,and susceptibility to interference.Its modeling and controller design have become the main difficulties to be solved.This paper mainly studies the modeling of hydraulic variable pitch system and the design of its controller.The main work of the paper includes:(1)Modeling and Stability Analysis of Wind Turbine Hydraulic Motor Pitch SystemFirstly,according to the basic structure and working principle of the hydraulic motor variable pitch system,the transfer function model of the hydraulic motor variable pitch system is established by means of dynamic analysis and Laplace transformation,and the dynamic characteristics of the system are determined.In order to further improve the modeling accuracy,the hydraulic module in Sim Hydraulics is adopted,and the physical simulation model of hydraulic motor variable pitch system is constructed by means of physical network.Finally,the classical control theory is used to analyze the stability of the transfer function model and the physical simulation model,and thestability of the model is verified,which provides a theoretical basis for the design of the variable pitch controller in the next chapter.(2)Design of hydraulic pitch control system based on artificial bee colony algorithm-RBF neural network-PIDAiming at the characteristics of high-order multi-coupling to the variable pitch system of hydraulic motor and uncertain parameters.In this chapter,the artificial bee colony algorithm is first used to obtain a set of PID controller parameter values??through offline optimization,which improves the tracking performance of the hydraulic motor pitch system.Then combined with RBF neural network,an adaptive moment estimation algorithm is introduced to adjust the controller parameters online,thereby improving the adaptability of the system.The simulation results show that,compared with the ordinary RBF neural network-PID control algorithm,the algorithm in this chapter has a smaller tracking error and a shorter time to recover to steady state when the pitch Angle signal changes,which has a better control performance.(3).Design of hydraulic motor pitch system based on finite time command filter backstepping controlConsidering that the wind turbine hydraulic variable pitch system is not only affected by itself,but also affected by external noise interference,high-frequency pitch angle signals and external loads to some extent,so this paper proposes a finite time command filter Step control strategy.Based on the design idea of the backstepping algorithm,firstly,the noise contained in the system state variable is removed by using the finite time command filter.Then the intermediate virtual quantity of the control algorithm is designed.In order to avoid the phenomenon of "differential expansion",the finite time command filter is used to approximate the differential of the intermediate control quantity.Then the finite time compensation mechanism is designed to ensure the accuracy of the filter signal,the control rate of the whole system is derived,and the liapunov function is designed based on the finite time theory to prove the tracking performance of the control system.Finally,the design experiments verify the control performance of this chapter’s design algorithm under the normal working conditions,the noise and friction working conditions and the high-frequency signal input working conditions.Compared with the PID algorithm based on artificial swarm optimization and the backward step control algorithm based on finite time expander differentiator,it is proved that the algorithm in this chapter has better control performance.