Jun-Ning Chen

Complex Intermittency in Switching Converters

Intermittent instability is commonly observed in switching power supplies during the design and development phase. It manifests as symmetrical period-doubling bifurcation in the time domain with long intermittent periods. Such intermittent operation is considered undesirable in practice and is usually avoided by appropriate adjustments of circuit parameters. This paper explores the mechanism and conditions for the emergence of intermittency in a common voltage-mode controlled buck converter. It is found that interference at frequencies near the switching frequency or its rational multiples will induce intermittent operation. The strengths and frequencies of the interfering signals determine the type and period of intermittency. The problem is analyzed by transforming the conventional parameter-bifurcation analysis to a time-bifurcation analysis. Analytical results are verified by simulations and experimental measurements.

Controlling chaos in DC/DC converters using optimal resonant parametric perturbation

The method of resonant parametric perturbation is a simple non-feedback chaos control method which is easy to implement in practice. In this paper, an optimal strategy is applied to stabilize an unstable orbit in a chaotically operating current-mode controlled buck-boost converter. Optimal values of initial phase angles are computed corresponding to minimum perturbation amplitudes. With this optimal perturbation, the converter operating in a chaotic regime can be controlled to operate in an unstable period-1 orbit that exists in the original chaotic attractor.

Modeling and simulation of Boost converter in CCM and DCM

this paper introduced the operation principle of current mode control Boost converter. The equations of two different work states were built by applying the theory of KCL and KVL. Two models working in CCM and DCM were respectively established using Matlab / Simulink and the nonlinear phenomenon of Boost converter can be observed through simulation. The results of theoretical analysis are corresponded with simulation and it can confirm these models are correctness and feasibility. It was also studied the change of these parameters impacting on the bifurcation and it can find the change of these parameters impacting on the stability of the converter. So, it can provide a reliable instruction for the stability design of Boost converter.

Complex Phenomena in SEPIC Converter Based on Sliding Mode Control

A hysteretic current-controlled SEPIC converter, which uses the sum of two inductor currents as the control variable, is discussed. The operation states of the converter are studied based on the theory of sliding mode control. The equivalent control and relative differential equations on the sliding surface are derived, based on which, the stability of equilibrium point is analysed with the calculation of eigenvalues. With numerical calculation and computer simulation, it is shown that the equilibrium point will lose the stability via a Hopf bifurcation when the current reference increases. Subsequently the converter will exhibit complex dynamical behavior including limit cycle, double limit cycle, quasi-periodicity, and chaos by increasing the current reference furthermore.

Principle of designing slope compensation in PFC Boost converter

Due to wide input fluctuation with line frequency of 50 Hz, power-factor-correction (PFC) Boost converters tend to exhibit fast-scale instability over time domain. The traditional remedy is to impose slope compensation so as to weaken or eliminate this instability. A theoretical principle on the implementation of slope compensation signal is still lacking. Empirical design will induce over compensation frequently, resulting in a large decrease of power factor. In order to tackle this issue, by constructing the discrete-time iterative map of the PFC Boost converter from the viewpoint of bifurcation control theory of nonlinear systems, consequently, the criterion of critical stability for the PFC circuit can be established. Based on this stability criterion, appropriate design of slope compensation can be achieved. Our work indicates that 3 main circuit parameters (i.e. switching cycle, output reference voltage and inductor) determine the effective amplitude design of the slope compensation signal. The results, validated by a large quantity of analytical and numerical studies, show that appropriate slope compensation can be effective in weakening (or controlling) fast-scale bifurcation while maintaining a rather high input power factor.

Research of Noise Induced Intermittent Chaos in Power Converter

This paper analyzes the working process of current-mode controlled Boost converter and finds that the system will produce the physical phenomenon of intermittency chaos when the converter works in the period windows of chaos zone and external noise reaches certain intensity. It can observe the phenomenon of noise-induced intermittent chaos and it also analyzes the relationship between noise intensity and induced intermittent chaos, the relationship between the noise intensity threshold and circuit parameters in resulting intermittent chaos from the perspective of numerical simulation. The research has an important theoretical and practical significance to nonlinear science and it can provide a reliable theoretical reference for the stable design of switching power converters.

Study of Control Chaos by Resonant Parametric Perturbation in H Bridge Converter

This paper introduces the phenomenon of nonlinear chaos of the peak current mode to control H bridge converter that has been known to become chaos for wide parameter variations after simulating to the model of H bridge converter. The natural reason of nonlinear phenomena can be explained by theoretical analysis. According to the characteristics of H bridge converter, resonant parametric perturbation was provided to suppress chaotic behavior of the converter and made the system changing from chaos to stable period. It is an effective non-feedback method for controlling chaos and it is such a suitable control method for controlling chaos in non-autonomous systems. Selecting the best perturbation phase to achieve the best chaos control results can optimize the method of resonant parametric perturbation. The control method suppresses chaos with high efficiency and it can provide theoretical basis for stability design of H bridge converter.

Study of Breathing Phenomenon in H Bridge Converter

This paper analysis the work principle of peak current mode H bridge converter. It can observe the system exhibits a kind of special nonlinear phenomenon: breathing phenomenon. When the disturbance signal frequency is not different with the switching frequency and there is a certain degree of disturbance signal intensity, it will produce breathing phenomenon through the modeling and numerical simulation to the system. We can know the theoretical analysis is same with the numerical simulation. At last, it discusses the change of circuit parameters Iref, E, L / T to impact degree of disturbance signal intensity to generate breathing. It can provide theoretical basis for stability design of H bridge converter.

Intermittent chaos and subharmonics in current-mode controlled SEPIC converters

Intermittent phenomena are commonly observed in periodically driven switching power converters. This paper explores the intermittent chaos and subharmonics in a current-mode controlled SEPIC converter using a circuit model with intruding interference. The theoretical analysis and computer simulation are prensted, which indicate that the signal strength and frequency of the intruding interference are vital parameters that affect the type and the period of intermittency.

Dynamical behaviour and stability analysis in SEPIC converter based on sliding-mode control

Abstract A hysteretic current-controlled SEPIC converter, which uses the sum of two inductor currents as the control variable, is discussed. The operation states of the converter are studied based on the theory of sliding-mode control. The equivalent control and relative differential equations on the sliding surface are derived, based on which, the stability of equilibrium point is analysed with the calculation of eigen-values. With numerical calculation and computer simulation, it is shown that the equilibrium point will lose the stability via a Hopf bifurcation when the reference current increases. The other circuit parameters will make influence on the first bifurcation point of reference current. Subsequently, the converter will exhibit complex dynamical behaviour, including limit cycle, double limit cycle, quasi-periodicity and chaos, by increasing the reference current furthermore.