Design Of Nonlinear Controller For Power System Based On Dissipativeness

Benefit from the huge capacity of power system and its complex power structure,under the premise of stable operation of the power grid,the power grid can not only produce huge economic benefits,but also effectively improve people’s livelihood.However,when large-scale power failure occurs in the power grid,it will be accompanied by huge economic loss and social impact.Therefore,it is very important to improve the stability of power system and give full play to the advantages of power grid.Aiming at the nonlinear mathematical model of power system,this paper designs several coordinated controllers based on coordinated passivation algorithm to improve the stability of power system.Firstly,for the single machine infinite bus power system with generator excitation,the excitation controller designed by Backstepping method and the energy controller based on dissipation are analyzed and studied.The dynamic performance of the two controllers is verified by simulation.Secondly,proposes an improved robust coordinated passivation method based on passivity for the nonlinear power system with Thyristor control series compensation（TCSC）and generator excitation.Based on the traditional coordinated passivation control method,sliding mode control,error compensation term,Minmax method,integral term and class-? function is added to improve the convergence rate of the system,enhance the transient performance and reduce the steady-state error of the system.The good dynamic performance of the proposed controller is verified by simulation.Then,for nonlinear power systems with static synchronous compensator and generator excitation,nonlinear compensation terms are used to estimate the upper bounds of virtual variables and disturbances in the proposed improved robust coordinated passivation method to simplify the controller form.And the adaptive law of uncertain parameters is designed by using Immersion and invariance theory.The effectiveness of the proposed controller is verified by simulation.Finally,the nonlinear power system with generator excitation,steam turbine speed control system and TCSC is studied.By introducing the switching strategy and considering the input constraints,the steam turbine governor system is modeled as two subsystems by using both main valve control and fast valve control.Using the improved robust coordinated passivation method,the controllers and switching strategy of TCSC,main valve,fast valve and generator excitation are designed respectively for the two subsystems.Simulation results show the effectiveness of the proposed controller.