POWER SUPPLY FOR A NON LINEAR LOAD WITH MULTILEVEL MATRIX CONVERTERS

摘要

A non linear load (2) is supplied with electric power by means of a power supply device (1). The non linear load (2) is in the form of an arc furnace (25) having an upstream furnace transformer (26). The power supply device (1) has a plurality of converter units (4). The converter units (4) each have a plurality of main modules (5). The main modules (5) each have an input connection (6) that is connected to a respective phase of a polyphase three phase power supply (3). The converter units (4) each have a common star point (7) that is connected firstly to a respective output (8) of the main modules (5) of the respective converter unit (4) and secondly via an output connection (9) of the respective converter unit (4) to the primary side (27) of the furnace transformer (26). The main modules (5) each have a series circuit comprising a coupling inductance (10) and a plurality of submodules (11). The submodules (11) each have a submodule input (12) and a submodule output (13) and in between a bridge circuit (14) having four self commutated semiconductor switches (15) and a bridge path (16). The bridge path (16) contains a respective storage capacitor (17). The semiconductor switches (15) of the submodules (11) can each be switched independently of the semiconductor switches (15) of the other submodules (11) of the same main module (5) and of the other main modules (5).