Current Source Converter as an Effective Interface to Interconnect Microgrid and Main Grid

Abstract

Back-to-back current source converters play an important role in high power applications. However, this back-to-back converter system uses a larger number of power switches, which is associated with more cost and the power density of the converter system can be affected. To address this issue, in this paper, a novel nine-switch back-to-back current source converter is proposed. To realize proper modulation of this nine-switch converter system, the concept of ampere balance is revisited at first. Then, its relationship with the traditional modulation scheme is revealed. Moreover, based on the ampere balance, the real-time dwell time calculation method is developed, where the tracking of rectifier current and inverter current is taken into consideration simultaneously. Finally, simulation results verify the effectiveness of the proposed modulation scheme.