Robust Distributed Cooperative Controller for DC Microgrids with Heterogeneous Sources

In a dc microgrid, a conventional solution for the primary control is droop control, which is achieved by imposing a virtual impedance on each converter. Its main drawbacks are the current sharing inaccuracy and the voltage deviation. To address these problems, we propose a robust distributed cooperative controller, which is an alternative to the droop mechanism. The controller is distributed in the sense that each one exchanges information with its neighboring converters, and hence no central controller is required. It is robust in the sense that parameters of power sources or load are not directly used to determine the controller parameters. A rigorous mathematical analysis is presented to guarantee the stability of the proposed controller, and simulation results are included to validate it.