The application of saturable turn-on snubbers to IGBT bridge-legcircuits

摘要

The turn-on loss of high-speed insulated gate bipolar transistorsn(IGBTs) accounts for a significant proportion of the total switchingnenergy. In many applications, this loss is increased by the energynassociated with diode reverse recovery of current. Such energy isnabsorbed by the IGBT switch at high voltage. Linear turn-on snubberninductors may be used to control the turn-on loss, diode reversenrecovery, and electromagnetic compatibility (EMC). These snubbers haventhe disadvantage of involving substantial stored energy that must benreset, normally by dissipation. An alternative is to use a saturablenturn-on snubber inductor, which stores substantially less energy than anlinear inductor. In this paper, the suitability of saturable turn-onnsnubber inductors for use with IGBTs is investigated, and possiblencircuit topologies for single-ended and bridge-leg applications arenproposed. Mathematical analysis, simulation, and practical results arenpresented for the saturable inductor turn-on snubber circuit topologies