Shui-Sheng Qiu

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The buck converter has been known to exhibit chaotic behavior in a wide parameter range. In this paper, the resonant parametric perturbation method is applied to control chaos in a voltage-mode controlled buck converter. In particular, the effects of phase shift and frequency mismatch in the perturbing signal are studied. It is shown that the control power(More)
This paper studies the “intermittent” chaos and subharmonics observed in switching dc/dc converters using a simple circuit model that describes possible unintended coupling of some weak spurious signal to the converter. The study shows that the signal strength and frequency of the intruding signal are vital parameters that affect the type of intermittent(More)
This paper investigates the coexisting fast-scale and slow-scale bifurcations in simple dc/dc converters under peak current-mode control operating in continuous conduction mode. Our focus is the boost converter as it is a representative form of dc/dc converter requiring current-mode control. Effects of varying the input voltage and some chosen parameters on(More)
This paper investigates the interaction of fast-scale and slow-scale bifurcations in the boost converter under current-mode control operating in continuous conduction mode. Effects of varying some chosen parameters on the qualitative behaviors of the system are studied in detail. Analysis is performed to identify the different types of bifurcation.(More)
This paper presents an improved resonant parametric perturbation method for controlling chaos. The control target can be any periodic orbit. Anti-control of chaos or chaotization is also possible using this method. Application of the method is illustrated for a common current-programmed dc/dc converter which can easily become chaotic for a wide parameter(More)
In this paper an approach is proposed for synchronizing chaotic systems, taking the viewpoint of a special characterization of chaotic attractors in which spiraling and excursion orbits are identified as the basic constituents. The proposed synchronization method takes advantage of the fact that a chaotic attractor is strongly characterized by excursion(More)
An algorithm of identifying the strength of random-like property of discrete chaotic sequences is proposed, and then several discrete chaotic maps are analyzed with this method. The pixel position of a color image is permutated by a stronger random-like discrete chaotic sequence, then the image is encrypted by a hyperchaotic sequence. Security analysis of(More)
This paper studies the “intermittent” chaos and subharmonics observed in switching dc/dc converters using a simple circuit model that describes possible unintended coupling of some weak spurious signal to the converter. The study shows that the signal strength and frequency of the intruding signal are vital parameters that affect the type of intermittent(More)
Four sets of magnetic diagnostic coils, which are printed on machinable ceramic printed circuit boards (PCB), are designed, fabricated, installed, and tested in the Joint Texas Experimental Tokamak (J-TEXT) vacuum vessel for detecting the plasma radial and vertical displacements relative to the geometric center of the vacuum vessel in Ohmic discharges. Each(More)
Abstract—We study a class of switching systems whose dynamics are characterized by an inner switching feedback loop and an outer continuous control loop. The loops have two widely separated time scales, performing fast-scale and slow-scale dynamics accordingly. Treating the two time scales separately, the stability of the systems can be studied, with(More)
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