System for electrical energy quality improvement

摘要

A system is composed of an active parallel compensator comprising coupling filters (3,4,5) in each phase conductor (L1, L2, L3) and an AC/DC power electronic converter, and/or a dynamic voltage restorer system comprising in each phase conductor a transformer (Tr1, Tr2, Tr3) and a coupling filter (7, 8, 9) and AC/DC power electronic converters (10, 11, 12) and an energy storage in the form of a storage capacitor (C1) included at DC terminals of said converters (6, 10, 11, 12). In each phase conductor in the LCLR type coupling filters (3, 4, 5; 7, 8, 9) each of resistors is replaced by an energy recovery system composed of a half-bridge system of power electronic switch (16 ,17, 18; 26, 27, 28) connected by means of chokes (D1, D2, D3; D4, D5, D6) and a voltage and current measurement block (13, 14, 15; 23, 24, 25) to the coupling filter in place of a replaced resistor, and signal conductors of the voltage and current measurement block are connected to the switch. In the active parallel compensator circuit, capacitors (C2, C3) connected in series are coupled to both outputs of each of the switches (16, 17, 18) and form an intermediate energy storage, wherein the latter by means of a power electronic converter (22), with an input circuit being galvanically isolated from a DC/DC output circuit, is connected to terminals of a storage capacitor (C1). Common point of the capacitors (C2, C3) is connected to a neutral conductor (N) and by means of the voltage and current measurement blocks (13, 14, 15) to one of the outputs of the coupling filters (3, 4, 5). In the dynamic voltage restorer system circuit, separately for each phase, capacitors in series (C4, C5; C6, C7; C8, C9) are coupled to both outputs of each of the power electronic switches (26, 27, 28) and by means of individual converters (32, 33, 34) they are connected to the storage capacitor (C1). For each phase respectively, common point of the capacitors (C4, C5; C6, C7; C8, C9) is connected by means of the voltage and current measurement block (23, 24, 25) to one of the outputs of the coupling filter (7, 8, 9).