A Highly Integrated 25-Level Cascaded H-Bridge Active Filter for the Mitigation of High Order Current Harmonics

The increasing share of power electronics in the conversion and distribution of electrical energy represents a novel challenge for energy quality and supply stability. It is to be expected that high-frequency current harmonics will increase significantly with the number of grid-connected power converters. To reduce the associated disadvantages, this paper presents a 25-Level Cascaded H-Bridge Active Filter for mitigating converter-induced current harmonics in the kilohertz range. Compared to conventional active filters, the proposed use of a voltage-source active filter does not require high control bandwidth, tuning to specific frequencies or measurement and tracking of high frequency currents. The highly integrated design on printed circuit boards allows a high number of voltage levels and a high power density at small additional effort and costs. A 12 kVA-demonstrator is used to mitigate the switching frequency current harmonics of a grid-connected two-level converter, verifying the effectiveness of the active filter configuration.