VERFAHREN UND VORRICHTUNG ZUR SPEISUNG EINES DREHSPANNUNGSNETZES MIT BELASTBAREM NULL-LEITER.

摘要

In order to maintain a predetermined three-phase voltage system at the output terminals (L1, L2, L3) of a transformer device TE without a connected primary star point (e.g. a transformer in delta/star connection), even when an asymmetric load is connected thereto and to the star point on the secondary side, single-phase transformers are used whose primary windings are supplied from a pulse-width modulated three-phase invertor in a bridge circuit. The actual values of the line voltage (UL1', UL2') on the secondary side form the control voltages (UA<*>, UB<*>, UC<*>) for each pair of bridge arms by means of voltage controllers (REA, REB). The control loops of the three phase voltages are disentangled on the basis of the structure of the transformation device by means of an organising element (EF). The nominal values can be synchronised to a synchronising voltage, and/or current regulation for the conductor currents is superimposed on the voltage controllers.