MULTILEVEL CONVERTER AS REACTIVE POWER COMPENSATOR WITH ACTIVE POWER BALANCING

摘要

FIELD: electricity.;SUBSTANCE: application: in the field of electric engineering. A multilevel converter (7) has several converting lines (8-10) which are wye- or delta-connected to phases (2-4) of the three-phase network. On the basis of phase voltage (U2-U4) values and phase current (IL2-IL4) values an active component (w) and at least two asymmetric components (w', b') are determined. The active component (w) and at least two asymmetric components (w', b') are filtered by means of the respective filter response. The phase voltage (U2-U4) values are multiplied by the component (w) and by at least two components (w', b'), whereupon they are multiplied by the respective weight coefficient (ga-gc) and the result is applied to the phase current (IL2-IL4) values. Current (I0) is determined in the neutral wire on the basis of components (w', b') and values (U2-U4) and applied to the phase current (IL2-IL4) values. Based on the phase current (IL2-IL4) values modified in this way the control state (A) is defined for the converting lines (8-10). The converting lines (8-10) are thus controlled respectively.;EFFECT: higher efficiency and reliability.;17 cl, 2 dwg