Popis: |
Auxiliary power supply for modern railway vehicles, powered from the DC catenary line, today is typically connected to the line through an inverter, and an output three-phase transformer. Generally, inverter includes DC component in its output voltage because of difference in switching behaviour of power devices which are used in the power converters. DC component leads to the magnetic field saturation of the transformers, which causes energy loss, and acoustic noise. Therefore, it is necessary to prevent the appearance of DC component on the inverter output. This paper proposes the basic methods used in practice to reduce adverse effects of DC component on the operation of three-phase transformer. |