Abstract: Apparatus for controlling the voltage supplied to a load, comprising: a multi-phase transformer having a primary and a secondary winding for each phase, each secondary being connected in series between an input line and an output directed to the load; and the primary is configurable by switches such that the phase of the voltage of the secondary is different from the line to which it is connected by a phase different from 0 and 180 degrees.

Abstract: Power supply apparatus includes a power factor corrector (PFC) unit, which is adapted to receive an AC voltage from an AC source, and to smooth the AC voltage while adjusting a waveform of an AC input current from the AC source relative to the AC voltage so as to generate a PFC output voltage made up of a DC component with a residual AC ripple. A regulator is coupled to receive an indication of a ripple amplitude and a ripple phase of the residual AC ripple and to generate, responsive thereto, a correction voltage which is combined with the PFC voltage to generate a DC output voltage in which the AC ripple is substantially reduced relative to the PFC voltage.