Active Disturbance Rejection Control Of Hydraulic Turbine Governing Systems

The hydraulic turbine governing system(HTGS)is a nonlinear system that integrates hydraulic,mechanical,and electrical components,and its stability is the key to ensuring the safe operation of hydropower units.In the actual operation of a power station,unit vibration,load increase or decrease,pressure pulsation in pressure pipes and draft tubes,and component wear can all affect the stable operation of the HTGS.In addition,with the large-scale grid connection of new energy sources such as wind energy and solar energy,hydropower is required to have stronger peak shaving and frequency modulation capabilities and more precise control.Based on the theory of auto disturbance rejection control(ADRC)and the mathematical model of water turbine,this paper applies ADRC to the HTGS,and studies the control performance of ADRC for hydropower units under different operating conditions.The main content of this article is as follows:(1)ADRC for linear hydraulic turbine governing systems.Firstly,the dynamic characteristics of the diversion system,hydraulic servo system,hydraulic turbine system,and generator system are analyzed,and a mathematical model of the HTGS is established using a modular approach.Secondly,using the principle of coordinate transformation,the mathematical model of the HTGS is transformed into a standard model of ADRC.Then,a tracking differentiator,an extended state observer,and a nonlinear state error feedback law are designed in order to form an ADRC.In addition,the convergence of the controller is analyzed using Lyapunov stability theory.Finally,the good performance of the controller under different operating conditions is analyzed through numerical simulation.(2)Nonlinear ADRC for HTGS considering dead zone.Aiming at the nonlinear characteristics of the electro-hydraulic servo system,a mathematical model of the HTGS with dead zone and mechanical time delay is established through analysis.Then,using the unique disturbance estimation and compensation capabilities of the extended state observer,a novel active disturbance rejection controller is designed to effectively handle the dynamic characteristics of the HTGS,such as nonlinear dead zones,time delays,and random disturbances,through active disturbance rejection.Combining the characteristics of PID integration to eliminate steady-state errors,a novel nonlinear ADRC is designed.The simulation verifies the effectiveness of the designed controller in the hydraulic turbine governing system.(3)Improved ADRC for nonlinear HTGS.A class of four dimensional single unit single tube nonlinear HTGS is considered,and the feedback linearization theory is used to transform the system into a model suitable for ADRC.Then,by analyzing the differential tracker,extended state observer,and nonlinear state error feedback laws of the improved ADRC,an ADRC suitable for nonlinear HTGS is designed.Finally,numerical simulation verifies the superiority of the controller.(4)Parameter optimization of ADRC based on marine predator algorithm.In order to solve the problem that the parameters of the ADRC are difficult to adjust,a marine predator algorithm is introduced.Using the structural characteristics of ADRC for a time-varying HTGS,the state error and controller output are taken as objective function variables,and the ocean predator algorithm is used to tune and optimize the ADRC parameters online.Finally,by comparing with other optimization algorithms,the effectiveness of the algorithm is verified,and the control performance of the controller for the HTGS is improved.