Distributed Secondary Control in DC Microgrids with Low-Bandwidth Communication Link

In this paper, a distributed secondary power sharing approach with low bandwidth communication network is proposed for low voltage direct current (LVDC) microgrids. Conventional droop control causes voltage drop in the grid and also a mismatch on the current of converters in the case of consideration of the line resistances. Proposed control system carry out the current value of the other converters to reach the accurate current sharing and suitable voltage regulation as well. Voltage and current controllers locally regulate the voltage and current of converters as a secondary controller. Secondary controller is realized locally and the communication network is only used to transfer the data of dc currents. Therefore, the secondary controller can regulate the average voltage by only using the data of currents. The proposed approach is verified with simulations based on PLECS.