Research On Chaotic Suppression Of Power System Based On Fixed Time

The power system will undergo bifurcation and chaos under certain conditions,which will appear as irregular oscillation,subsynchronous resonance or voltage collapse,which poses a threat to the safe operation of the system.With the rapid development of the interconnection trend of large power grids,improving the interconnected power system model and further studying the chaotic identification and control issues of interconnected power systems will help to improve the stability of the power system and have important significance for the safe and stable operation of the power system.In this paper,the phase space method of nonlinear dynamics and the bifurcation theory are used to analyze the chaotic oscillations of the second-order and fourth-order interconnected power systems in Chapters 2 and 4 respectively,and the nonlinear operating state of the system is clarified.And detailed analysis of the mechanism of bifurcation and chaos behavior.At the same time,based on the fixed time principle,a new adaptive controller is designed to realize the chaos control of the second-order and fourth-order power systems.Secondly,this paper generalizes the second-order power system model to fractional order,analyzes the chaotic characteristics of the fractional model by chaotic attractor graph,and improves the sliding mode control based on saturation function with the fixed time principle.By designing a new sliding mode in this paper,an adaptive nonvibration fixed-time sliding mode control strategy is proposed to control the power system fractional-order model to a predetermined target.Numerical simulations show that the designed fixed-time sliding mode controller controls the transition time is shorter and the transition is smoother.Finally,the disturbance and drift problems of the chaotic oscillation model parameters of power system are easily generated.A method based on fixed-time synchronization parameter observer is proposed.Considering that the approximate range of parameters of the system can be determined in engineering practice,the identification rules are based on the approximate error and synchronization error of the identified parameters,and the feedback tuning coefficients and parameter adaptive laws of the fixed-time synchronized observer are adjusted online in real time.Realize the identification of model parameters.Theoretical analysis and numerical simulation results show that the fixed-time synchronized observer method is much better than the synchronous observer method in terms of identification stability and accuracy of identification results.The research on the analysis,identification and control of chaotic phenomena in power system lays a good foundation for the development and update of chaotic control of power system based on fixed time.