| Abstract |
Railway traction power supply systems can be fed directly from the public three phase grid, if they
operate at the same frequency. The railway substations are high power single phase loads causing
high unbalanced line currents and, due to voltage drops at line impedances, negative sequence voltage
components. In this paper a shunt inverter arrangement is described to compensate these negative
sequence line currents. The inverter consists of three full-bridge modules with neutral point clamped
three-level topology. Two different modulation strategies are discussed, which use off-line computed
pulse patterns for harmonic elimination. A phasor oriented control scheme is presented for the use
with these modulation techniques. To show the dynamic control performance, simulation results are
presented. |
