A Fully Soft-Switched Single Switch Isolated DC–DC Converter

Abstract

This paper proposes a soft-switched single switch isolated converter. The proposed converter is able to offer low cost and high power density in step up application due to the following features: ZCS turn-on and ZVS turn-off of switch and ZCS turn-off of diodes regardless of voltage and load variation; low rated lossless snubber; reduced transformer volume compared to flyback based converters due to low magnetizing current. Experimental results on a 100kHz, 250W prototype are provided to validate the proposed concept.Index Terms-Isolated step-up dc-dc converter, single switch, soft switching. 0885-8993 (c)

A single stage soft-switched AC/DC power factor corrected converter with galvanic isolation

“…Isolated AC/DC converters are used in many applications, such as PC's and consumer electronics, uninterruptible power supplies, telecommunication power supplies [1,2,3,4,5,6,7,8,9,10]. Sever isolated AC/DC converter topologies with active PFC have been proposed [1,2].…”

“…However, these topologies suffers from high switch losses with the drawback of many switch component needed, and this often results in an overall efficiency of less than 90%. Several single stage schemes have been reported in the literature [6,7,8,9,10]. They have the features such as lower component, lower cost, smaller size and high power conversion efficiency than the two stage schemes.…”

“…An passive-clamp circuit is proposed to limit the switch voltage excursion and realize the soft-switch for power switch and diode [10], but it suffers from excessive power losses dissipated in RCD snubber. This paper proposes a single-phase single-stage soft-switched AC/DC isolated converter, and the basic active-clamp operation of the ZVS single-stage converter is analyzed and explained.…”

“…1 shows the single-stage isolated PFC AC/DC topology. The AC/DC topology includes a diode bridge and a isolated boost converter [8,10]. The proposed converter consists of switches Q 1 and Q 2 , which are shown with their associated antiparallel diode.…”

“…Q 1 and Q 2 are main and auxiliary switches respectively. During the turn-off of the main switch Q 1 , it will produce high voltage spikes at switch Q 1 , so a clamp circuit is essential part of the topology [10].…”