Passive lossless snubbers for DC/DC converters

Abstract

A general passive lossless snubber cell is proposed for use in DC/DC converters. The snubber is to suppress the turn-on loss of a MOSFET resulting from the reverse recovery current of the freewheeling diode. Energy recovery is achieved since the energy absorbed by the snubber during turn-on can be delivered to the output during turn-off. The simple structure and the absence of active components and resistors make this snubber a good alternative to a conventional RCD snubber or an active snubber. As an example, a boost converter equipped with the snubber is analysed. A 1 kW, 100 kHz prototype is implemented in the laboratory, and efficiency of 97% has been measured. Six basic non-isolated DC/DC converters equipped with the proposed snubber cell are also illustrated.