If you want to sneak DC into a system, you'd never get it passed a clamp meter, if you just use some diodes. You'll need serious decoupling. I say serious, because the load is substantial and will quickly drain the reservoir capacitors. Any ripple on the DC will generate a varying magnetic field, albeit small if your ripple is small, and this variation is what a clamp meter picks up.
Anyway... next piece of equipment on the shopping list (for the next test) ought to be http://www.tortech.com.au/category/3-phase-isolation/ Plug everything into an isolation transformer. That should do it. .s
