Coexisting Fast-Scale and Slow-Scale Instability in Current-Mode Controlled DC/DC Converters: Analysis, Simulation and Experimental Results

Chen, Yanfeng; Tse, Chi Kong; Shui-sheng, Qiu; Lindenmuller, Lars; Schwarz, Wolfgang

doi:10.1109/tcsi.2008.923282

Cited by 83 publications

(3 citation statements)

References 18 publications

(32 reference statements)

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“…Such an approximation is more accurate for the boost converter for which the capacitor voltage is piecewise linear than for the buck topology for which the capacitor voltage is piecewise quadratic. In terms of the output capacitance, the closed-form expression at the bifurcation boundary can be expressed as For K cri < K flip < K, it may happen that period-doubling bifurcation coexists with low-frequency oscillation [52], since, in this case, the converter will operate in CCM and an open-loop converter with a CPL operating in this mode is unstable at the slow scale. This will give rise to a mixed mode of operation in which, during some cycles, DCM will take place in the subharmonic regime, and during other cycles, CCM will occur, showing instability at the slow scale.…”

Section: Fixed Point and Its Stabilitymentioning

confidence: 99%

Bifurcation Phenomena in Open-Loop DCM-Operated DC–DC Switching Converters Feeding Constant Power Loads

et al. 2023

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Constant power loading is an effect that appears in multiple-stage energy conversion systems with individually regulated switching power converters. In a two-stage system, an upstream or source converter drives one or more downstream or load converters. The downstream converters in a two-stage power conversion system are designed to provide the fastest transient response in stand-alone operation. Consequently, they behave as a constant power load (CPL) to the upstream converter within their control bandwidth. In the past, open-loop power converters feeding CPLs and operating in discontinuous conduction mode (DCM) were considered to be stable. In this paper, it is shown that these systems can undergo instabilities, which have been so far overlooked. First, numerical simulations from the switched model of an open-loop boost converter under DCM operation and loaded with a tightly regulated buck converter and the same converter loaded by an ideal CPL are presented to show that they exhibit similar nonlinear behavior and bifurcation phenomena. Then, the three elementary open-loop DC–DC converters operating in the DCM were considered and their bifurcation phenomena were revealed. It is shown that the period-doubling route to chaos in the DC–DC boost converter is interrupted by a sudden appearance of dangerous destructive dynamics due to the excessively unlimited load current in the CPL. For the buck converter, only the first period-doubling bifurcation is observed before the destructive behavior appears. The open-loop buck–boost converter under DCM and feeding a CPL is always unstable and exhibits no periodic orbit. Based on the observed phenomena, approximate discrete-time models were derived, which despite their simplicity, were seen to display the most-important and -essential features of the corresponding switching converters before destructive dynamics occurs.

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Section: Fixed Point and Its Stabilitymentioning

confidence: 99%

Bifurcation Phenomena in Open-Loop DCM-Operated DC–DC Switching Converters Feeding Constant Power Loads

et al. 2023

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“…However, it is commonly accepted that converters with PCM control are confronted with instability issues [4,5]. A wide variety of nonlinear dynamic phenomena, such as bifurcations and chaos, have been observed in these converters [6][7][8][9][10][11][12][13], which could deteriorate the performances of the converters, and are undesired in practice. As a result, the active duty ratio of PCM control in DC-DC converters is usually restricted in the range of (0, 1/2) in continuous-conduction-mode (CCM) and (0, 2/3) in discontinuous-conduction-mode (DCM) [14,15].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Stability in a PCM-Controlled Boost Converter with the Target Period Orbit-Tracking Method

et al. 2019

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Thee peak-current-mode (PCM) control strategy is widely adopted in pulse width-modulated (PWM) DC-DC converters. However, the converters always involve a sub-harmonic oscillating state or chaotic state if the active duty ratio is beyond a certain range. Hence, an extra slope signal in the inductor-current loop is used to stabilize the operation of the converter. This paper presents a new technique for enlarging the stable range of PCM-controlled DC-DC converters, in which the concept of utilizing unstable period-1 orbit (UPO-1) of DC-DC converters is proposed and an implementation scenario based on the parameter-perturbation method is presented. With the proposed technique, perturbations are introduced to the reference current of the control loop, and the converters operating in a chaotic state can be tracked, and thus be stabilized to the target UPO-1. Therefore, the stable operating range of the converters is extended. Based on an example of a PCM-controlled boost converter, simulations are presented as a guide to a detailed implementation process of the proposed technique, and comparisons between the proposed technique and techniques in terms of ramp compensation are provided to show the differentiation in the performance of the converter. Experimental results in the work confirm the effectiveness of the proposed technique.

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“…As the duty cycle progresses, the system turns unstable, and when the slope value is very high, subharmonics are present [37,38], limiting the time response of the controlled system [39] and compromising performance [40]. In this way, it is necessary to find the correct compensation ramp value to avoid a fast scale related to the inner control loop [41,42] or a slow scale due to the outer control loop [43,44]. Both dynamic behaviors have been widely studied in reference to several converters [45][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

Slope Compensation Design for a Peak Current-Mode Controlled Boost-Flyback Converter

et al. 2018

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Peak current-mode control is widely used in power converters and involves the use of an external compensation ramp to suppress undesired behaviors and to enhance the stability range of the Period-1 orbit. A boost converter uses an analytical expression to find a compensation ramp; however, other more complex converters do not use such an expression, and the corresponding compensation ramp must be computed using complex mechanisms. A boost-flyback converter is a power converter with coupled inductors. In addition to its high efficiency and high voltage gains, this converter reduces voltage stress acting on semiconductor devices and thus offers many benefits as a converter. This paper presents an analytical expression for computing the value of a compensation ramp for a peak current-mode controlled boost-flyback converter using its simplified model. Formula results are compared to analytical results based on a monodromy matrix with numerical results using bifurcations diagrams and with experimental results using a lab prototype of 100 W.

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Coexisting Fast-Scale and Slow-Scale Instability in Current-Mode Controlled DC/DC Converters: Analysis, Simulation and Experimental Results

Cited by 83 publications

References 18 publications

Bifurcation Phenomena in Open-Loop DCM-Operated DC–DC Switching Converters Feeding Constant Power Loads

Bifurcation Phenomena in Open-Loop DCM-Operated DC–DC Switching Converters Feeding Constant Power Loads

Improvement of Stability in a PCM-Controlled Boost Converter with the Target Period Orbit-Tracking Method

Slope Compensation Design for a Peak Current-Mode Controlled Boost-Flyback Converter

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