Active Power Flow Control Between DC Microgrids

The interconnection of de microgrids may help to address the problems associated with uncertainty of renewable energy generation systems. In this paper, a load flow converter (LFC) is proposed which interconnects two adjacent de microgrids and controls bidirectional power flow between them. The LFC needs to regulate power by applying and controlling a voltage in between two de grids. Generation of this series-voltage, if done by using the same grids, will be of immense advantage. Therefore, a new concept of input-parallel and output-series connection is proposed. The LFC is formed with a dual active bridge followed by a full-bridge dc-dc converter. It injects dynamic voltage in series with the transmission line to control power flow between the de grids. The required power rating of the LFC is fairly low compared to the power transmitted between de grids and also it does not require any external power source for operation. The proposed configuration is simulated in MATLAB/OPAL-RT-based real-time simulation platform. A scaled-down version of the system (at 30 V level) is developed in the laboratory to experimentally validate the concept. The results show the effectiveness of the LFC for interconnection of de microgrids.