Application Research Of Active Disturbance Rejection Control Technology In Thermal Power Units

With the mainstreaming of ultra-supercritical thermal power units,the characteristics of the controlled object’s non-linearity,strong disturbance,and strong coupling have become prominent.In particular,the uncertainty of the interference has reduced the control performance of the PID controller.Therefore,a new controller is urgently needed to meet higher control needs.Active disturbance rejection controllers stand out with good immunity performance and robustness,and can well balance the contradiction between fastness and overshoot in process control.Therefore,this paper designs an active disturbance rejection controller for a typical thermal power plant Control loop to improve the overall performance of the thermal process.This paper analyzes in detail the basic architecture and control algorithm of ADRC and the influence of adjustable parameters.The controller type is designed based on the order of the controlled object,in which the second-order and above-order controlled objects are designed as a second-order nonlinear ADRC and the first-order controlled object is designed as a first-order linear ADRC.In addition,a method for tuning linear ADRC parameters based on PID parameter information and a method for tuning nonlinear ADRC controller parameters based on particle swarm optimization are proposed.Aiming at the single-variable thermal process and cascade thermal process of thermal power units,this paper selects the typical controlled objects: the outlet air temperature of the coal mill,the condensate water level of the low-pressure heater,and the cascade control of the superheated steam’s temperature reduction water System,the first-order linear ADRC,second-order nonlinear ADRC and ADRC-LADRC cascade controll are designed respectively,and the multi-objective particle swarm algorithm is used to tune the cascade controller.Simulation and analysis on Matlab / Simulink software show that the rules of parameter tuning are feasible,and the ADRC controller has good control performance.Finally,on the EDPF-NT Plus platform of the domestic DCS system,an ADRC was built through the embedded algorithm module and applied to the actual thermal control loop.The field application results show that the ADRC controller can be configured on the DCS platform of the thermal power unit and it is feasible to replace the PID controller.It has good engineering application value.This research has laid the foundation for the application of ADRC in other control loops of thermal power plants.