Economic Power Sharing to Minimize Generation Cost in a DC Microgrid

This study developed an economic power-sharing method to minimize the total generation cost (TGC) in a DC microgrid based on an AC signal injection technique. Economic power sharing for each distributed generator (DG) is achieved by means of a small AC frequency without a communication network. The AC frequency is proportional to the DG's incremental cost and is injected into the output voltage of the DG. The AC signal frequency is indirectly regulated to have economic power sharing with equivalent incremental cost for each DG, so the minimization of TGC is achieved instead of a straightforward optimization solution. Therefore, the control scheme is simple and easy to implement. The proposed power-sharing method overcomes the impact of differences in line resistance and is realized in a decentralized manner without a communication network and with plug-and-play capability. The proposed control method was investigated theoretically and verified experimentally.