On the AC-Connecting of a System for Active Filtering and Regeneration in Active DC-Traction Substations

This paper presents a new approach in the AC-connection filter design of a shunt active power filter based on three-phase voltage source inverter. The practical case study is of a LCL passive filter with damping resistors connected to the output of the inverter in an active DC-traction substation with 12-pulse parallel diode rectifier. Starting from the functions to be fulfilled, the design conditions are based on the transfer function related to the input and output currents. They consist of imposing the magnitude response at the switching frequency, as well as the position of the resonance frequency relative to the frequency of the highest order harmonic to be compensated. The design algorithm is fully formulated, some limitations are expressed and specific performance indicators are proposed. Through simulation in Matlab-Simulink environment, the proper operation of the whole system, including the designed interface filter, is illustrated.