Method for providing DC voltage sections in power supplies having semiconductor AC power controllers

摘要

In an AC load (1) to which a supply voltage which is present at the output of a mains-supplied semiconductor AC power controller (2) which is controlled by control pulses from a controller (8, 9, 10, 11) is applied, it is intended to ensure that there is either no DC voltage component, or only a defined, small DC voltage component, in the supply voltage. This is done by driving the semiconductor switches of the AC power controller (2) asymmetrically in the two mains half-cycles. For this purpose, the DC component is detected via a DC voltage filter (3) and is compared in a regulator (4) with a reference variable which corresponds to a predetermined, desired DC voltage component in the supply voltage. The control deviation of the regulator (4) influences, as an additional control variable, a synchronising voltage in the mains filter (8) of the controller of the AC power controller (2), as a result of which asymmetric control pulses are formed. <IMAGE>