Research On Dynamic Bifurcation Behaviors And Stability Controls Of Boost Converter With Switched-Inductor

With the rapid development of engineering technologies,high-performance DC-DC converter with high efficiency,high gain and high reliability has received extensive attention in the domain of power electronics.The new technologies such as switched-inductor,switched-capacitor and interleaved parallel structure have gradually become the key research direction of scholars at home and abroad.However,when the circuit parameters change or the external environment interferes,the instability behaviors such as bifurcation,subharmonic oscillation and chaos of the DC-DC converter may greatly reduce the performance of the system.With the further research on nonlinear phenomena,especially the vigorous development of nonlinear theories in the field of power electronics,people have gradually realized that the strong nonlinear characteristic of converter is the essential reason of bifurcation and chaos.Therefore,applying nonlinear theories to DC-DC converter and adopting appropriate chaos control strategies have important guiding value for improving the stability of the converter.Based on the nonlinear theories,the dynamic characteristics of switched-inductor Boost converter are studied in this paper,and the nonlinear analysis of interleaved parallel switched-inductor(IPSI)Boost converter with more complex structure is carried out.Based on the previous research on chaos control strategies,the optimal stability controls of switched-inductor Boost converter under peak current-mode control(PCMC)are carried out,the concrete works are as follows:(1)The switched-inductor Boost converter is studied,and the topology structure of the system under PCMC is constructed,and the characteristics and principles of the system in continuous current mode(CCM)are analyzed.Then,the circuit model is constructed in Simulink,and the important connections between the variation of different parameters and the characteristics of nonlinearity of the system are described through the analysis of the bifurcation diagrams and maximum Lyapunov exponents.The typical working states of the system under different parameters are studied by means of nonlinear methods such as Poincare section.Finally,the correctness of numerical simulations is verified by PSIM software.(2)On the basis of(1),combined with the interleaved parallel technology,the structure of IPSI Boost converter under PCMC is constructed.In order to study the instability mechanism of the converter,four working modes and the corresponding mathematical models of the system are given when the duty cycle is less than 0.5.Furthermore,the bifurcation diagrams are used to study the important influence of parameter changes on the performance of the converter.The results show that,compared with interleaved parallel Boost converter,the stability range and voltage gain of IPSI Boost converter are more significant due to the embedded switched-inductor structure.Then,the discrete mapping model of the system is constructed,and the Jacobian matrix eigenvalue method is used to explore the instability mechanism of the converter.Finally,PSIM is also used to verify the nonlinear phenomena of IPSI Boost converter.(3)Based on the principle of resonant parametric perturbation,the parameter conditions of sinusoidal signal which can make the switched-inductor Boost converter achieve the desired chaotic control effect are analyzed.The theoretical stability criterion is given,and the corresponding optimal phaseθand disturbance amplitude A are calculated.Then,combining the advantages of charge control and resonant parametric perturbation,the compensation signal generated by the one-cycle reset integral compensation structure is designed and used to control the stability of the system,and the reference signal I_c is given for the system to achieve the desired stability effect when the circuit parameters change.Finally,PSIM is used to compare the chaos control effects of the two strategies with the slope compensation method.The results show that both of the two strategies make the unstable system return to steady state,and the peak value of inductor current does not deviate from the reference signal,which effectively avoids the deficiency of slope compensation,and the dynamic response performance of the system under the one-cycle reset integral compensation is better.