Distributed Finite-Time Secondary Control for DC Microgrids with Reduced Internetwork Data Transmission Dependency

In this paper, a distributed secondary controller is proposed for DC microgrids (DCMGs) with reduced dependency on information from neighboring units, while achieving voltage consensus, current sharing, and reference voltage tracking tasks. Adopting a distributed finite-time secondary controller from the literature, we use the physical relations in the DCMG network to eliminate the dependency of the local controllers on the voltage information of the neighboring units. This is done by using the local measurements of the load and the unit currents and the line resistances to achieve voltage consensus in the network. Another revision is to modify the control law for the unit responsible for tracking the reference voltage from an external tertiary controller in the interconnected network setting. We propose to release this unit from any responsibilities except for the reference voltage tracking. Finally, we propose to include a saturation function on the secondary controller with an integrator anti-windup logic to maintain the system voltages within a safe limit. Simulation results indicate that the proposed controller provides superior performance compared to the conventional controller in achieving all of the desired control objectives for the DCMGs.