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Technical Dialogue

Power Factor Correction: CCM, DCM, CRM/BCM Control, Bridgeless

D01.1 - Design and Placement of a Passive Clamp Snubber for Isolated SEPIC and Cuk Converters Working as Automatic Power Factor Correctors

Thursday, March 20, 2025
11:30 AM – 1:30 PM ET
Location: Level One, Hall A3
DC/DC power converters with galvanic isolation using only one power transistor need elements that limit the voltage peaks at the beginning of the transistor turn off process. These elements are called clamp snubbers. Its placement and design are well known for power converters with two reactive elements (e.g. flyback). However, different placements can be considered for these clamp snubbers in converters with higher number of reactive elements. Moreover, if the converter works as a Resistor Emulator in a Power Factor Corrector (PFC), the snubber design must take into account the continuous variation of some of the electrical variables. This paper presents the study of four different placements for a passive clamp snubber network in a SEPIC converter working as an automatic PFC. The value of the clamp snubber resistor needed to achieve a specific clamp voltage for these four options is determined in the paper. Moreover, the four options are compared in terms of the dissipated power in the snubber resistor. The study carried out for the SEPIC topology is also valid for the Cuk one. Finally, the results obtained have been verified by both simulation and experimental results.