The synchronization of a novel fractional-order memristorbased chaotic system is investigated.And an adjustable adaptive controller is designed to achieve the synchronization of this system.By adjusting the control coefficients of the controller,drive-response system can achieve many different types of synchronization such as adaptive synchronization,projective synchronization and antisynchronization.The sufficient condition for the synchronization has been analyzed by the stability theory of fractional-order differential system.Finally,numerical simulations are used to demonstrate that the proposed adaptive controller is effective and correct.
For the purpose of investigating the nonlinear dynamics of the system,a fractional-order Chua's circuit based on the memristor deriving from the integer-order counterparts is provided. Firstly,according to the Lyapunov's indirect method,the stability analysis of the memristive system is made,and it shows that when the fractional-orders parameter of memristive system passes a critical value,the system loses the stability and bifurcation occurs. Then the bifurcation and chaos behaviors of fractional-order memristive system are show n using bifurcation diagrams w ith varying fractional orders of the system and other parameters. Furthermore,the chaotic behaviors of memristive chaotic system are proved by the waveform,phase plot and largest Lyapunov exponent diagram. Finally,theoretical results are illustrated and validated with the given numerical simulations.
According to the fact that the actual inductor and actual capacitor are fractional, the mathematical and state-space averaging models of fractional order Buck converters in continuous conduction mode(CCM) are constructed by using fractional calculus theory. Firstly, the parameter conditions that ensure that the converter working in CCM is given and transfer functions are derived. Also, the inductor current and the output voltage are analyzed. Then the difference between the mathematical model and the circuit model are analyzed, and the effect of fractional order is studied by comparing the integer order with fractional order model. Finally, the dynamic behavior of the current-controlled Buck converter is investigated. Simulation experiments are achieved via the use of Matlab/Simulink. The experimental results verify the correctness of theoretical analysis, the order should be taken as a significant parameter. When the order is taken as a bifurcation parameter, the dynamic behavior of the converter will be affected and bifurcation points will be changed as order varies.
Based on Lyapunov theorem and sliding mode control scheme,the chaos control of fractional memristor chaotic time⁃delay system was studied.In order to stabilize the system,a fractional sliding mode control method for fractional time⁃delay system was proposed.In addition,Lyapunov stability theorem was used to analyze the control scheme theoretically,which guaranteed the stability of commensurate and non⁃commensurate order systems with or without uncertainties and disturbances.Furthermore,to illustrate the feasibility of controller,the conditions for designing the controller parameters were derived.Finally,the simulation results presented the effectiveness of the designed strategy.
As an important research branch,memristor has attracted a range of scholars to study the property of memristive chaotic systems.Additionally,time⁃delayed systems are considered a significant and newly⁃developing field in modern research.By combining memristor and time⁃delay,a delayed memristive differential system with fractional order is proposed in this paper,which can generate hidden attractors.First,we discussed the dynamics of the proposed system where the parameter was set as the bifurcation parameter,and showed that with the increase of the parameter,the system generated rich chaotic phenomena such as bifurcation,chaos,and hypherchaos.Then we derived adequate and appropriate stability criteria to guarantee the system to achieve synchronization.Lastly,examples were provided to analyze and confirm the influence of parameter a,fractional order q,and time delayτon chaos synchronization.The simulation results confirm that the chaotic synchronization is affected by a,q andτ.
The integer order memristive time delay chaotic system has attracted much attention and has been well discussed.However,the fractional order system is closer to the real system.In this paper,a nonlinear time delay chaotic circuit based on fractional order memristive system was proposed.Some dynamical properties,including equilibrium points,stability,bifurcation,and Lyapunov exponent of the oscillator,were investigated in detail by theoretical analyses and simulations.Moreover,the nonlinear phenomena of coexisting bifurcation and attractor was found.The phenomenon shows that the state of this oscilator was highly sensitive to its initial value,which is called coexistent oscillation in this paper.Finally,the results of the system circuit simulation accomplished by Multisim were perfectly consistent with theoretical analyses and numerical simulation.
A sliding mode controller for a fractional-order memristor-based chaotic system is designed to address its problem in stabilization control.Firstly,aphysically realizable fractional-order memristive chaotic system was introduced,which can generate a complex dynamic behavior.Secondly,a sliding mode controller based on sliding mode theory along with Lyapunov stability theory was designed to guarantee the occurrence of the sliding motion.Furthermore,in order to demonstrate the feasibility of the controller,a condition was derived with the designed controller＇s parameters,and the stability analysis of the controlled system was tested.A theoretical analysis shows that,under suitable condition,the fractional-order memristive system with a sliding mode controller comes to a steady state.Finally,numerical simulations are shown to verify the theoretical analysis.It is shown that the proposed sliding mode method exhibits a considerable improvement in its applications in a fractional-order memristive system.
