Analysis on Rectifier Diode Stress Issue of the DCM Active Clamped Dual-Switch Forward Converter and its Solutions
ABSTRACT This paper illustrates the rectifier stress issue of the active clamped dual switch forward converters operating on discontinuous current mode (DCM), and analyzes the additional reverse voltage on the rectifier diode of active clamped dual switch forward converter at DCM operation, which does not appear in continuous current mode (CCM). The additional reverse voltage stress, plus its spikes, definitely causes many difficulties in designing high performance power supplies. In order to suppress this voltage spike to an acceptable level and improve the working conditions for the rectifier diode, this paper carefully explains and presents the working principles of active clamped dual switch forward converter in DCM operation, and theoretically analyzes the causes of the additional reverse voltage and its spikes. For conquering these difficulties, this paper also innovate active clamped snubber (ACS) cell to solve this issue. Furthermore, experiments on a 270 W active clamped dual switch forward converter prototype were designed to validate the innovation. Finally, based on the similarities of the rectifier network in forward-topology based converters, this paper also extents the utility of this idea into even wider dc-dc converters.
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- "Due to the issues of the classical forward converter which are high voltage stress and less than 50% duty cycle, many new topological variations and innovations have been developed. The discussions in the recent literatures focus on DC/DC converter   ; some of them are focused on bidirectional DC/DC power conversion  ; others are developing new single-stage AC/DC converter     . "
ABSTRACT: A new forward-based single-stage power-factor-corrected converter is proposed. A portion of input power is directly transferred to the output through the forward converter to improve the efficiency of power conversion. The flyback auxiliary circuit is added to the forward converter to reduce low line-frequency output voltage ripple. In an effort to lower the size and cost of the converter, a single transformer is used for all the power conversion with Time Multiplexing Control (TMC). The simulation results confirm the effectiveness of the proposed scheme with high power factor and tight output regulation.Power Electronics and Drive Systems, 2009. PEDS 2009. International Conference on; 12/2009
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ABSTRACT: The Full Bridge converter topology modulated in phase shift is one of the most popular converters used to obtain high efficiency conversion, especially in high power and high voltage applications. This converter topology combines the simplicity of fixed frequency modulations with the soft switching characteristic of resonant converters but, if a diode rectifier is used as output stage, it suffers of severe overshoot voltage spikes and ringing across the rectifier. In this paper, a new regenerative active snubber is widely studied and developed to reduce this drawback. The proposed snubber is based on a combination of an active clamp with a buck converter used to discharge the snubber capacitor. The snubber gate signal is obtained by using those of the phase shift modulation.01/2011; DOI:10.1109/APEC.2011.5744792