摘要:
A method is specified for operating a charger (1) for a voltage-maintaining device (2), in which a rectifier (5), connected to phase inputs (PA, PB; PC) via a transformer (3) with an electric AC voltage supply system (4), of the charger (1) is driven by means of a drive signal (S) formed from reference charging voltages (ULA, ref; ULB, ref; ULC, ref). Furthermore, a charging voltage (ULA; ULB; ULC) for the corresponding phase (A; B; C) is generated at each phase input (PA; PB; PC) a substantially constant DC voltage (UDC) being generated-on the DC voltage side of the rectifier (5). Each charging voltage (ULA; ULB; ULC) is generated in such a way that in the corresponding phase (A; B; C) a charging current (ILA; ILB; ILC) is injected in a fashion substantially proportional to a phase system voltage (UNA; UNB; UNC) of the corresponding phase (A; B; C) of the electric AC voltage supply system (3). An apparatus for carrying out the method is also disclosed.