| 摘要 |
<p>An apparatus and a method for filtering harmonics in a power transmission contact line (2) of a railway system. The apparatus includes a multilevel converter having one single phase leg (1), which phase leg comprises switching cells (11, 21), each switching cell (11, 21) comprises semi-conductor switches arranged to selectively provide a connection to a corresponding energy storage element. The multilevel converter also includes a controller (31) provided to control the switching of each switching cell (11, 21) and wherein the phase leg (1) is configured in two parallel branches (10, 20) of cascaded switching cells (11, 21), which branches (10, 20) are interconnected in a closed circuit. The controller (31) is provided to monitor the content of harmonics in the contact line (2) and is adapted to filter the monitored harmonics by means of adapting the switching of the switching cells to absorb the harmonics.</p> |
