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This paper presents the modeling, analysis, and design of a thyristor-based ac–dc converter, featuring bi-directional power flow and unity power factor at the ac side in both powering and regenerating modes. By applying the y-parameter modeling technique and eliminating the effects of the high-frequency poles and zeros, small-signal models of the converter in both modes and a unified controller have been developed. The controller regulates the voltage at the dc side and operates as a feedback controller in the powering mode and a feedforward controller in the regenerating mode. Systematic procedures for determining the circuit component values of the power conversion stage and the controller are presented. The operation is illustrated with the design of a 500-W, 100-V (ac)/200-V (dc) prototype, supplying to a motor-generator set. Experimental results showing operation in the powering mode, regenerating mode, and during mode changeover are included. Circuit operations during the transient of the changeover operation are clearly identified.

The two prevalent s-domain models for current-mode control, the continuous-time model and the unified model, exhibit noticeable differences in their small-signal predictions and therefore have become the subject of comparisons and clarifications. The current letter presents an alternative way of deriving the unified model, thereby providing an additional guide for assessing the validity of the unified model. This letter also presents experimental data that support the accuracy of the unified model.

Two case examples of high-speed CMOS microelectronic implementations of high-performance controllers for switching power converters are presented. The design and implementation of a current-programmed controller and a general-purpose feedforward one-cycle controller are described. The integrated circuit controllers attain high-performance by means of using current-mode analog signal processing, hence allowing high switching frequencies that extend the operation margin compared to previous designs. Global layout-extracted transistor-level simulation results for 0.8 μm and 0.35 μm standard CMOS technologies confirm both the correct operation of the circuits in terms of bandwidth as well as their functionality for the control of switching power converters. The circuits may be used either as standalone IC controllers or as controller circuits that are technology-compatible with on-chip switching power converters and on-chip loads for future powered systems-on-chip.

The aim of the paper is to investigate the bifurcation behavior of the power-factor-correction (PFC) boost converter under a conventional peak current-mode control. The converter is operated in continuous-conduction mode. The bifurcation analysis performed by computer simulations reveals interesting effects of variation of some chosen parameters on the stability of the converter. The results are illustrated by time-domain waveforms, discrete-time maps and parameter plots. An analytical investigation confirms the results obtained by computer simulations. Such an analysis allows convenient prediction of stability boundaries and facilitates the selection of parameter values to guarantee stable operation.

In the process of designing and constructing switching power converters, chaotic operations are often observed intermittently between long periods of regular operations. In practice, such intermittent chaotic operations can be eliminated by incorporating appropriate design measures to combat interference of spurious signals. In this paper, we explain the mechanism that causes "intermittent" chaos in a popular type of switching converters, namely, current-mode controlled switching converters. The circuit model used to study the phenomenon incorporates a coupling process through which a spurious signal is coupled to the current sensing and ramp compensation circuitry, resulting in a modulation of the compensation slope which causes the system to become unstable intermittently. We show that coupling of spurious signals into the compensation ramp can cause intermittent chaotic or subharmonic operations.

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. Boundaries of stable region, slow-scale bifurcation region, fast-scale bifurcation region, interacting fast and slow-scale bifurcation regions are identified.

Peak Current-Mode (PCM) and Valley Current-Mode (VCM) controlled switching dc-dc converters have symmetrical dynamical behaviors within a wide circuit parameter variation range. To investigate the symmetrical dynamical behaviors between PCM and VCM controlled switching dc-dc converters, the iterative map models and inductor current borderlines that exist in the bifurcation diagrams of both PCM and VCM controlled buck, boost, and buck-boost converters are established. The research results of bifurcation behaviors indicate that the bifurcation diagrams of PCM and VCM controlled switching dc-dc converters have symmetrical dynamical behaviors corresponding to a symmetrical point (SP). The simulation results show that time-domain waveforms of PCM and VCM controlled switching dc-dc converters working in periodic orbits have symmetrical axis and SP, and the SP also exists in corresponding phase portraits. Experimental results are given to verify the analysis and simulation results in this paper.