Abstract: The invention comprises a circuit arrangement with a first direct voltage to an alternating voltage transforming unit, an alternating voltage to a second direct voltage transforming unit, and a second direct voltage smoothing filter, connectable to a load, whereby the first direct voltage to an alternating voltage transforming unit has an inductance whose one connection is connected to a mutual connecting point for a two series connected rectifiers, and wherein the alternating voltage to a second direct voltage transforming unit includes a parallel related rectifier. A back current through one of two parallel related rectifiers, formed at the switching period of the alternating voltage, and a therefrom originating power contribution to the inductance, is redistributed by a power contribution redistributing organ, belonging to the transforming unit, in order to reduce the losses appearing, for instance in the series connected rectifiers.

Abstract: The invention relates to a method and a circuit arrangement for controlling power valves included in at least one converter (2,4) forming part of a converter circuit which on its input receives at least two DC voltages (U1,U2) and transmits current pulses respectively corresponding to these DC voltages to a common load (R.sub.L) via a common output filter (L1,C1), said controlling aiming at keeping the input DC voltages equal.A control circuit (44) regulates the input voltages by shifting the starting times of the respective current pulses with respect to each other. Preferably, and particularly in continuous operation, the respective current pulses are shifted with respect to each other essentially without changing there widths.