MULTI-LEVEL ACTIVE FILTER CONTROL SYSTEM Russian patent published in 2021 - IPC H02M1/15 

FIELD: electrical equipment.

SUBSTANCE: invention relates to electrical engineering and can be used in power high-voltage power supply systems with powerful controlled rectifying plants, for example, for arc furnace of direct current. Technical problem, solution of which is aimed at invention, consists in improvement of electric energy quality in electric network of DC arc furnace at all stages of furnace process, as well as increase in efficiency and reliability of power supply system operation. Technical problem is solved by the fact that multilevel active filter control system is equipped with phase automatic frequency control unit (10), first (11), second (12), third (13) and fourth (14) control subsystems, unit of pulse-width modulators (15), first (16) and second (17) pulse-width modulators, as well as unit for selection of control subsystem (18). Disclosed control system has a switching structure, a feature of which is selection of one of two control options: with suppression of harmonics in specified frequency range or with selective suppression of fifth and seventh harmonics depending on stage of technological process of DC arc furnace.

EFFECT: this provides low total harmonic components of electric circuit voltage at all stages of furnace process, that is improves electric power quality indicators; in addition, increasing efficiency and reliability of operation of electrical system "supply network - DC arc furnace - multilevel active filter".

1 cl, 1 tbl, 9 dwg