When people say recirculating currents in the context of a power system, do they mean Eddy currents? I'm just confused about the terminology and I couldn't find anything online to clarify this.
Eddy currents are currents magnetically induced in a ferromagnetic core. They're one of the forms of core loss, reducing the efficiency of switching inductors and transformers.
I've seen the phrase "circulation current" used in the context of a rectifier and inverter on the same line and DC bus. Every peak of the sine wave, the diodes in the rectifier conduct current out of the AC line and into the DC bus. But the inverter does the same thing in the opposite direction, taking current from the DC bus and putting it on the AC line. You can end up with a surprising amount of current flow that's simply "sloshing" back and forth between AC and DC, but never accomplishing anything. Especially if the conduction windows are of different lengths!
Now, this probably isn't the only use of the phrase, but I'd suspect other uses will be similar.