Steve Ward DRSSTC-4: full-bridge DRSSTC with fibre optic isolation

Four 40N60 minibrick IGBTs in a compact, low-inductance full bridge off a plain 160 VDC bus (120 VAC, no doubler), 350 A current limit, a minimal MMC of two 8 kV/100 nF caps. The fibre-optic receiver moved into its own shielded aluminium enclosure here. Noise on the signal pulse width had been traced to the fibre cable’s metal collar, and grounding it fixed the problem. The gate-drive transformer is custom, wound from ordinary Cat-5e cable on a ferrite toroid. The breakout point is at the toroid edge on purpose, so arc-backs land there and nothing blows up. This is the testbed the Universal Driver below was written up from.

Schematics and photos

Sources

• DRSSTC-4

This is the card from the driver tree, written from what the builder published. Send corrections through the forum.