A third way to shape the bus without a buck stage or a phase-shifted bridge. Let the current ring up past a setpoint, then turn every IGBT off at once. The tank’s energy regenerates back into the DC bus, with the bridge running as a rectifier for an instant, so the envelope falls exactly as fast as it rose. Steve Conner proposed it as a way to put a conventional over-current detector into something closer to PWM control. He is one of the three people loneoceans credits for inventing the DRSSTC itself. It was tried in practice on a UD3 by davekni, whose name turns up across years of the forum’s most technical threads, usually reviewing someone else’s driver rather than publishing his own. This is the only ramping work of his own that came up in the research for the tree.
Sources
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.