These components are employed in driving applications and other uses, to reduce harmonic components and commutation voltage dips, increasing reliability of the whole driving system and protecting both the equipment and the supply grid from low frequency disturbances. Power supply energy quality plays greater and greater role in power engineering, because each power supplier has legal duty to supply the customers with energy characterised by definite parameters, for example: harmonics contents, voltage amplitude, frequency, etc. To achieve this goal, we should limit the introduction into the grid the disturbances generated by different types of devices connected to the grid, especially those which consume distorted current from the grid.