99% efficiency DC-DC converter

The paper will present two novel Soft Switching Half Bridge Topologies used in a 1KW DC-DC Converter, operating after a PFC and providing an isolated 12V at 83A. The two topologies are derived from a conventional Half Bridge topology and through different means are converted to “true” soft switching topology. A “true” soft switching topology combines zero current at turn off in the secondary through the synchronous rectifiers and zero voltage switching across the primary switchers. This is accomplished in the first topology without any additional hardware, just through sizing and intelligent control. In the second topology, we add two small current “injectors” aimed in shaping the current through the rectifier means and primary switchers just during the transitions. In combination to a novel magnetic structure and intelligent control, this converter efficiency crosses the 99% efficiency barrier.