Harmonic and interharmonic currents compensation in DC line

In this paper a strategy for the compensation of harmonic currents in DC bus has been proposed. By means of a multilevel converter, low amplitude harmonic currents due to the interaction between primary converters operating in different conditions and connected to the same DC bus, are compensated. This strategy is suitable for the applications requiring a common DC bus such as Distributed Generations (DG) networks and it is able to avoid problems to devices connected due to low frequency harmonic currents. The compensator is modular and it is composed by cells series connected. It is controlled to minimize modulation current ripple. Thanks to the multilevel topology, the converter is able to operate in high voltage applications and permits to minimize the size of the switches. Simulations and experimental results demonstrate the effectiveness of the proposed solution.