CM voltage compensation in AC/DC/AC interfaces for smart grids

In this paper the results of research connected with common mode (CM) interference generated by four-quadrant frequency converters and effective methods of CM voltage compensation are presented. The obtained results show that conducted CM interference generated by these converters in a low voltage (LV) grid can be transferred by means of parasitic couplings into a medium voltage (MV) network and can be observed at distant points under overhead MV lines. The compensation of the CM voltage sources on both the input and the output sides of the AC/DC/AC converter using proposed arrangement of compensators significantly reduces unwanted, EMC related, side effects accompanying the application of AC/DC/AC interfaces in Smart Grids.