Component Design Considerations for Active RFI-Filters for Drives

Active EMI-filters for attenuating radio frequency interferences (RFI) have been discussed for years. Several research projects have shown the potential of active EMI-filters to reduce cost, volume and weight while increasing simultaneously the filter performance. However, the application of active EMI-filters has been limited to a few very specific applications. In this paper design considerations for the passive components of the sensing device are determined in order to enlarge the application area of active EMI-filters. A detailed feasibility study of possible sensing devices is presented and the results are confirmed by measurements