Characterization of an active clamp flyback topology for power factor correction applications
13 Feb 1994-pp 412-418
TL;DR: In this paper, the authors present the analysis, design, and experimental results of 500 W single stage and 600 W interleaved active clamp flybacks used for power factor correction, including the application of charge control, the use of mixed power devices, and a solution to the hold-up time problem.
Abstract: Flyback derived power convertor topologies have long been attractive because of their relative simplicity when compared with other topologies used in low power applications. Incorporation of active clamp circuitry provides the additional benefit of recycling transformer leakage energy while minimizing switch voltage stress. This paper presents the analysis, design, and experimental results of 500 W single stage and 600 W interleaved active clamp flybacks used for power factor correction. Several practical issues, including the application of charge control, the use of mixed power devices, and a solution to the hold-up time problem are discussed and experimentally verified. >
Citations
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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
Cites background from "Characterization of an active clamp..."
...Equation ( 5 ) can be used to develop a design equation determining an appropriate resonant inductor value that realizes ZVS at a desired operating point....
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...mentioned previously, it is assumed its value will be a small fraction of &. For a given converter operating point and value of Cr, achieving ZVS requires that Lr be of sufficient size to completely discharge the switch capacitance. At time instant T4, fiom Eq. ( 5 ):...
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24 Apr 1998
TL;DR: In this paper, basic types of DC-DC converter topologies are studied to investigate their self-PFC capabilities, their input characteristics are compared and their input line current waveforms are predicted.
Abstract: Basic types of DC-DC converters, when operating in discontinuous conduction mode, have self power factor correction (PFC) property, that is, if these converters are connected to the rectified AC line, they have the capability to give higher power factor by the nature of their topologies. Input current feedback is unnecessary when these converters are employed to improve power factor. In this paper, basic types of DC-DC converter topologies are studied to investigate their self-PFC capabilities. Their input characteristics are compared and their input line current waveforms are predicted.
230 citations
20 Jun 1994
TL;DR: In this paper, a new scheme of the single-phase parallel power factor correction (PPFC), which allows major input power to be processed only once to achieve both unity power factor and tight output regulation, is established.
Abstract: A new scheme of the single-phase parallel power factor correction (PPFC), which allows major input power to be processed only once to achieve both unity power factor and tight output regulation, is established in this paper. The new PPFC circuits based on this new scheme are much simpler than the previous one. Consequently, they are competitive to the conventional two-cascade-stage system concerning the efficiency and the cost. Large signal simulation and experimental results have proven the successful operation and good performances of the proposed new PPFC circuits. >
135 citations
TL;DR: In this paper, a novel power factor correction (PFC) cell, called flyboost, was proposed, which combines power conversion characteristics of conventional flyback and boost converters.
Abstract: A novel power factor correction (PFC) cell, called flyboost, is presented. The proposed PFC cell combines power conversion characteristics of conventional flyback and boost converters. Based on the flyboost PFC cell, a new family of single-stage (S/sup 2/) ac/dc converters can be derived. Prominent features of newly derived S/sup 2/ converters include: three power conversions, i.e., boost, flyback, and another isolated dc/dc power conversions are simultaneously realized that typically uses only one power switch and one simple controller; part of the power delivered to the load is processed only once; bulk capacitor voltage can be clamped to the desired level; and capable of operating under continuous current mode. Experimental results on example converters verify that while still achieving high power factor and tight output regulation, the flyboost PFC cell substantially improve the efficiency of the converter.
125 citations
01 Jun 2001
TL;DR: This paper presents the mechanisms that generate low-frequency and high-frequency electrical noise, lists the problems caused by the various noise types, provides an overview of the standards that establish noise limits, and discusses and evaluates the various mitigation techniques.
Abstract: A dramatic increase in the number of line-powered electronic equipment (computers and other office equipment, electronic ballasts, variable-speed drives, and consumer electronics, e.g., color televisions) has taken place. These items of equipment draw distorted, and often fluctuating, line current; they also generate high-frequency conducted and radiated noise due to the sharp edges of the waveforms characteristic of the switching power processors employed in them. As a result of the finite grid impedance, the distorted line current increases the distribution losses and causes voltage distortion; also, the fluctuation leads to visible flicker of the emitted light of lamps. The conducted and radiated high-frequency noise interferes with radio and TV reception, communication via cellular telephones, and data transmission. The result is a gradually deteriorating electromagnetic environment. This paper presents the mechanisms that generate low-frequency and high-frequency electrical noise, lists the problems caused by the various noise types, provides an overview of the standards that establish noise limits, discusses and evaluates the various mitigation techniques, and raises concerns regarding the impact of the circuitry that has to be added to the equipment to meet the harmonic limits and the pitfalls and deficiencies of the line-harmonics regulation standards.
108 citations
References
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11 Jun 1990
TL;DR: In this paper, a novel snubber circuit for high-frequency PWM (pulse width modulations) DC-toDC and DCto-AC converters is presented.
Abstract: A novel snubber circuit for high-frequency PWM (pulse width modulations) DC-to-DC and DC-to-AC converters is presented. The snubber is a series circuit of a capacitor and a snubber switch which is connected across the main switch. The main switch and the snubber switch are switched alternately with a short dead time. The condition of zero-voltage switching is satisfied both in the main switch and the snubber switch by applying the switched snubber. The turn-off surge due to parasitic inductance in the circuit and the recovery of the diode are eliminated by the switched snubber without increasing the voltage stress and the conduction losses in the main switch. >
113 citations
07 Mar 1993
TL;DR: In this paper, the authors applied the charge control concept to a flyback power converter for the purpose of power factor correction (PFC), which can operate in continuous conduction mode (CCM) with unity power factor.
Abstract: The charge control concept is applied to a flyback power converter for the purpose of power factor correction (PFC). Using charge control, a flyback converter can operate in continuous conduction-mode (CCM) with unity power factor. The simplicity of the flyback circuit is maintained and the power handling capacity is increased. The properties of charge control related to flyback PFC application are studied. The design guidelines are presented. A 200 W prototype circuit is built. Experimental results show good application prospects. >
100 citations
Patent•
04 Oct 1984
TL;DR: In this article, a power supply topology which minimizes inductance and capacitance requirements for filtering the ripple of single or multiple output switching mode power supplies is proposed, where a capacitor at the input of the power supply provides continuous support for the output signal produced by the power input.
Abstract: A power supply topology which minimizes inductance and capacitance requirements for filtering the ripple of single or multiple output switching mode power supplies. A capacitor at the input of the power supply provides continuous support for the output signal produced by the power supply.
68 citations