Steady-State Stability of Current-Mode Active-Clamp ZVS DC–DC Converters
TL;DR: In this paper, the steady-state and dynamic performance of the active-clamp dc-dc converters were analyzed for its dynamic behavior under current control, and a simple expression for the maximum duty cycle for subharmonic-free operation was obtained.
Abstract: Active-clamp dc-dc converters are pulsewidth-modulated converters having two switches featuring zero-voltage switching at frequencies beyond 100 kHz. Generalized equivalent circuits valid for steady-state and dynamic performance have been proposed for the family of active-clamp converters. The active-clamp converter is analyzed for its dynamic behavior under current control in this paper. The steady-state stability analysis is presented. On account of the lossless damping inherent in the active-clamp converters, it appears that the stability region in the current-controlled active-clamp converters get extended for duty ratios, a little greater than 0.5 unlike in conventional hard-switched converters. The conventional graphical approach fails to assess the stability of current-controlled active-clamp converters, due to the coupling between the filter inductor current and resonant inductor current. An analysis that takes into account the presence of the resonant elements is presented to establish the condition for stability. This method correctly predicts the stability of the current-controlled active-clamp converters. A simple expression for the maximum duty cycle for subharmonic-free operation is obtained. The results are verified experimentally.
Citations
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TL;DR: In this article, a dc-dc boost converter topology for low input and high output voltage applications was proposed, which consists of a three-winding coupled inductor, a single switch and two hybrid voltage multiplier cells.
Abstract: This paper presents a dc–dc boost converter topology for low input and high output voltage applications, such as photovoltaic systems, fuel cell systems, high-intensity discharge lamp, and electric vehicles. The suggested configuration consists of a three-winding coupled-inductor, a single switch and two hybrid voltage multiplier cells. Furthermore, two independent hybrid voltage multiplier cells are in parallel when the single switch S is turned on , and they are in series when the switch S is turned off . So, the advantages of the proposed converter structure are summarized as follows: 1) A coupled inductor with three windings is introduced in the presented converter structure. The two secondary windings of the coupled inductor are, respectively, used to form a hybrid multiplier cell on the one hand, on the other hand, it increases the control freedom of the voltage gain, enhances the utility rate of magnetic core and power density, and reduces the stress of power components to provide a stable constant dc output voltage. 2) The two hybrid multiplier cells can absorb synchronously the energy of stray inductance, which not only reduces the current stress of corresponding diodes, but also greatly alleviates the spike voltage of the main switch, which improves the efficiency. 3) The two hybrid multiplier cells are connected in series to supply power energy for the load, so the voltage gain is extended greatly due to this particular structure. Thus, low-voltage low-conduction-loss devices can be selected and the reverse-recovery currents within the diodes are inhibited. The operating principles and the steady state analyses of the proposed converter are discussed in detail. Finally, a test prototype has been implemented in the laboratory, and the simulated and experimental results show satisfactory agreement with the theoretical analysis.
85 citations
Cites background from "Steady-State Stability of Current-M..."
...Active-clamp circuits or resistance, capacitor and diode (RCD) snubbers can be used to address this issue [13], [14], but these clamp circuits are complex and costly....
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TL;DR: A unified three-terminal switch model for current mode controls with constant frequency and variable frequency modulations operating in continuous conduction mode is proposed, providing an accurate and simple equivalent circuit for various converters using current mode control schemes.
Abstract: Current mode controls have been widely used in many power converters with various topologies. Small signal equivalent circuit model is an effective tool for controller design. However, no unified equivalent circuit model applicable to various converters is available. This paper proposes a unified three-terminal switch model for current mode controls with constant frequency and variable frequency modulations operating in continuous conduction mode, providing an accurate and simple equivalent circuit for various converters using current mode control schemes. By identifying the invariant three-terminal structure in current mode control pulsewidth modulation (PWM) converters, which consists of active switch, passive switch, inductor, and closed current loop, the terminal current and voltage relationships are studied and represented by a small signal equivalent circuit. A small signal model for a current mode control PWM converter can be obtained by point-by-point substitution of the PWM switch with its equivalent circuit. The proposed model is verified by simulation and experimental results of various converters, and compared with other models to demonstrate its accuracy. The proposed model is accurate up to half of switching frequency.
77 citations
TL;DR: In this article, the authors discuss about the various DC-DC converter configurations with high voltage conversion ratio utilized in DC micro-grid structures and compare them based on voltage conversion ratios, duty ratio, efficiency along with the basic operating principle.
Abstract: This manuscript discuss about the various DC-DC converter configurations with high voltage conversion ratio utilized in DC micro-grid structures. The presented DC-DC converter topologies play a major role globally in the power generation sector including micro-grid, because of its decreased number of semiconductor devices, maximum conversion efficiency, small in size and cost of manufacturing is less. In this manuscript the DC-DC converter are categorized in to isolated and Non-isolated topologies. The first group topography works with the presence of transformer and the second group works without the transformer. These converters are capable to provide the various stages of output range. Researchers utilize these converters in the area of renewable energy generation, electric vehicle, micro sources, charge pumping applications etc. Hence they also work to improve the efficiency and reliability with reduction in components numbers and economical aspect. In this manuscript, the various topography of DC-DC converter topologies utilized in micro-grid are reviewed and comparison is made based on voltage conversion ratio, duty ratio, efficiency along with the basic operating principle. This review also reveals the research gaps, current trends, and challenges in the last part.
72 citations
TL;DR: In this paper, a soft-switching single-ended primary inductor converter (SEPIC) was proposed to obtain ripple-free input current and achieve zero-voltage switching operation of the output diode.
Abstract: A soft-switching single-ended primary inductor converter (SEPIC) is presented in this paper. An auxiliary switch and a clamp capacitor are connected. A coupled inductor and an auxiliary inductor are utilized to obtain ripple-free input current and achieve zero-voltage-switching (ZVS) operation of the main and auxiliary switches. The voltage multiplier technique and active clamp technique are applied to the conventional SEPIC converter to increase the voltage gain, reduce the voltage stresses of the power switches and diode. Moreover, by utilizing the resonance between the resonant inductor and the capacitor in the voltage multiplier circuit, the zero-current-switching operation of the output diode is achieved and its reverse-recovery loss is significantly reduced. The proposed converter achieves high efficiency due to soft-switching commutations of the power semiconductor devices. The presented theoretical analysis is verified by a prototype of 100 kHz and 80 W converter. Also, the measured efficiency of the proposed converter has reached a value of 94.8% at the maximum output power.
58 citations
Cites methods from "Steady-State Stability of Current-M..."
...Among them, the active clamp technique is often used to limit the voltage spike effectively, achieve soft-switching operation, and increase the system efficiency [16]–[21]....
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TL;DR: In this article, a closed-loop inductance capacitance inductance-T (LCL-T) series parallel resonant converter has been simulated and presented in a MATLAB environment.
Abstract: A closed-loop inductance capacitance inductance-T (LCL-T) series parallel resonant converter has been simulated and presented in this article. The fuzzy logic controller has been used for closed-loop operation, and the performance of the proposed converter has been estimated with a closed-loop condition. The steady-state stability analysis of the LCL-T series parallel resonant converter has been analyzed using the state-space model and simulated using MATLAB (The MathWorks, Natick, Massachusetts, USA). The proposed approach is expected to provide better voltage regulation for dynamic load conditions. A prototype 300-W, 100-kHz converter is designed and built for experimental demonstrations, and transient and steady-state performances for the LCL-T series parallel resonant converter are compared from the simulation studies.
39 citations
Cites background from "Steady-State Stability of Current-M..."
...[8] demonstrated an active clamp zero voltage switching (ZVS) DC-DC converter....
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References
More filters
20 Jun 1994
TL;DR: In this paper, the behavior of the ZVS active-clamp flyback operating with unidirectional magnetizing current is analyzed and design equations based on this analysis are presented.
Abstract: Flyback derived power convertor topologies are attractive because of their relative simplicity when compared with other topologies used in low power applications. Incorporation of active-clamp circuitry into the flyback topology serves to recycle transformer leakage energy while minimizing switch voltage stress. The addition of the active-clamp circuit also provides a mechanism for achieving zero-voltage-switching (ZVS) of both the primary and auxiliary switches. ZVS also limits the turn-off di/dt of the output rectifier, reducing rectifier switching losses, and switching noise due to diode reverse recovery. This paper analyzes the behavior of the ZVS active-clamp flyback operating with unidirectional magnetizing current and presents design equations based on this analysis. Experimental results are then given for a 500 W prototype circuit illustrating the soft-switching characteristics and improved efficiency of the power converter. Results from the application of the active-clamp circuit as a low-loss turn-off snubber for IGBT switches is also presented.
421 citations
18 Jun 1979
TL;DR: In this article, an analysis of dc-to-dc switching converters in constant-frequency current-programmed continous conduction mode is performed, and leads to two significant resuslts.
Abstract: An analysis of dc-to-dc switching converters in constant-frequency current-programmed continous conduction mode is performed, and leads to two significant resuslts. The first is that a ramp function, used to eliminate a potential instability, can be chosen uniquely to assure both stability and the fastest possible transient response of the programmed current. The second is the development of an extension of the state-space averaging technique by means of which both the input and output small-signal properties of any such converter may be accurately represented by a linear small-signal equivalent-circuit model. The model is presented and experimentally verified for the cuk converter and for the conventional buck, boost, and buck-boost converters. All models exhibit basically a one-pole control-to-output transfer fuction response.
271 citations
"Steady-State Stability of Current-M..." refers background in this paper
..., mc = m2 removes any error after one switching period, commonly known as “dead beat control” [12]....
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...Ramp compensation is a standard remedy to overcome the subharmonic instability [12]....
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...Ramp compensation is a standard remedy to overcome the subharmonic instability in current-programmed converters [12]....
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...This is referred as “subharmonic instability” in literature [12]....
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...The converter output is controlled by the choice of the peak switch current is(t) [12]....
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01 Jun 1981
TL;DR: A new linear, small-signal modeling technique, called sampled-data modeling, succeeds, where state-space averaging fails, in predicting the subharmonic instability in current-programmed regulators, and is shown to be of significant usefulness in the design of high-performance switching regulators.
Abstract: The high-frequency capabilities of two switching regulator modeling techniques, state-space averaging and discrete modeling, are compared. A new linear, small-signal modeling technique, which combines the continuous form of state-space averaging with the accuracy of discrete modeling, is then developed. This new method, called sampled-data modeling, succeeds, where state-space averaging fails, in predicting the subharmonic instability in current-programmed regulators, and is shown to be of significant usefulness in the design of high-performance switching regulators.
230 citations
"Steady-State Stability of Current-M..." refers background in this paper
...Nonlinear dynamics and the instability modes have been studied in detail for the currentcontrolled hard-switched dc–dc converters [13]–[20]....
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TL;DR: In this paper, the authors studied the bifurcation paths exhibited by a simple second-order DC/DC boost converter under current-programmed control with and without voltage feedback.
Abstract: This paper studies the bifurcation paths exhibited by a simple second-order DC/DC boost converter under current-programmed control with and without voltage feedback. Previous work in this area has reported two distinct types of bifurcation paths, namely via regions of quasi-periodic orbits and period-doubling. This paper demonstrates that the two different types of bifurcation paths can, in fact, be viewed as part of another bifurcation in which the quasi-periodic sequence transmutes into the period-doubling sequence, and that such a bifurcation is observed regardless of the presence of the outer voltage feedback loop as long as a suitable set of bifurcation parameters is chosen. The describing iterative map is derived in closed form and is used to develop the main results via a series of computer experiments. The characteristic multipliers are calculated and the first onset of flip-bifurcation is predicted. Computer simulation based on an exact piecewise switched model confirms the predicted bifurcations. The exhibition of quasi-periodic orbits is confirmed by computation of the Lyapunov exponent. Finally, a series of return maps are generated to provide an alternative viewpoint to the reported bifurcations in terms of a transmutation from a tent-like map to a logistic-like map.
189 citations
"Steady-State Stability of Current-M..." refers methods in this paper
...Several methods have been suggested in the investigation of the nonlinear behavior of switched-mode dc–dc converters [14], [15]....
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TL;DR: In this article, approximate transfer functions of series and parallel resonant converters are given which are in good agreement with the results of exact analysis as well as the results obtained in experiments, and it is shown that the dominant behavior of these transfer functions is determined by the output low-pass filter modified by the internal impedance of the converter.
Abstract: Approximate transfer functions of series and parallel resonant converters are given which are in good agreement with the results of exact analysis as well as the results of experiments. It is shown that the dominant behavior of these transfer functions is determined by the output low-pass filter modified by the internal impedance of the converter. The high-frequency behavior, on the other hand, is given by a second-order response whose frequency is at the difference between the resonant and the switching frequencies and whose Q is the original resonant Q modified by the internal impedance of the converter. >
186 citations