Ward's next generation added phase lead, so the bridge switches slightly ahead of the current zero and the IGBTs turn on soft. It was still being tuned three years after first light: comparator biasing, capacitor values matched to specific modules. Loneoceans' DRSSTC 2 ran this board, described as “a modified driver originally designed by Steve Ward, which uses Phase Lead for ZCS”.
Schematics and photos
schematic: “DRSSTC Driver, Steve Ward 2010”, rev B sheet updated 26 Mar 2011 
schematic: the original UD2.1, “Steve Ward 2009” (sheet printed 27 Oct 2009)
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.