SIRIO AC and ACS single-phase converters are totally isolated from the mains:
AC-MCF model by optoisolated reference
AC model with firing pulses sent to the gate via transformer, and auxiliary power supplies are made of a transformer with rectifiers and stabilizers
ACS model: it has the same features of the AC model; in addition, in the ACS model, a transformer obtains the voltage feedback, and a current transformer obtains the current feedback.
The waveform being symmetrically split into both positive and negative half-wave, the average value of the output voltage is not altered, and it is equal to zero.
Therefore, it is possible to power the single-three-phase loads without generating a circulation current in the mesh, with an average value different from zero.