| As a basic power electronic equipment,DC-DC converter has complex nonlinear characteristics.It is of great significance to analyze the nonlinear dynamic characteristics of the converter system and overcome the harmful nonlinear behaviors such as chaos to ensure its stable operation.In order to analyze the nonlinear behavior characteristics of the converter system under the load of memristor,this paper takes the voltage-controlled memristor as the load,and studies the dynamic characteristics and chaos suppression method of the current mode controlled(PCMC)capacitive Boost converter system through modeling and simulation analysis.The main work of the study is as follows:Firstly,modeling of memristor load and converter.Firstly,the nonlinear function is used to express the characteristics of the memristor,and the voltage controlled model of the memristor is established by simulation circuit,and the model is simulated and analyzed by MATLAB and PSIM.The state equations of the capacitive Boost converter in continuous current mode(CCM)and discontinuous current mode(DCM)under PCMC were derived,and the numerical model and circuit model were established.MATLAB and PSIM were used to simulate and analyze the converter system respectively.Secondly,the nonlinear stability of the converter system is studied.According to the proposed discrete state-space model of the converter,the effects of reference current,input voltage,inductance and load type on the nonlinear dynamic characteristics of the system are described by bifurcation diagram and maximum Lyapunov exponential analysis.Then,nonlinear methods such as Poincare cross section are used to analyze the specific states of the system under different parameters.For the case of inductance coupling,taking the coupling coefficient k =0.1 as an example,the nonlinear characteristics of inductance under the forward and reverse coupling are analyzed,and the influence of the coupling coefficient on the system stability is explored by using the bifurcation diagram as a variable.Finally,PSIM is used for simulation verification.Thirdly,chaos control of converter system.Aiming at the nonlinear chaos instability of the converter,the effects of parametric resonance micro-perturbation method,dynamic slope compensation method and segmental delay feedback control on the system chaos control are analyzed.First,a three-dimensional bifurcation diagram is constructed with disturbance amplitude a and signal phase shift φ as variables,and the value range of disturbance parameters is discussed.Then,the control parameter selection of dynamic slope compensation method and piecewise delay feedback method is discussed respectively.The simulation results show that the three chaos control strategies can effectively control the chaotic behavior.In conclusion,the nonlinear behavior and chaos suppression of capacitive Boost converters under memristor load are studied comprehensively in this paper,and the proposed method can be extended to the stability analysis of other converter systems. |
