Constant power loads (CPLs) impose instability issuesin DC microgrids due to their negative impedance characteristics.This paper studies the problem of voltage control design of DCmicrogrids with CPLs. It is assumed that the power of CPLs isuncertain and belongs to a given interval leading to an infinitenumber of equilibrium points of the system. We develop a polytopemodel for DC microgrids with uncertain CPLs. Using this model, arobust two-degree-of-freedom feedback-feedforward voltage control framework is then proposed. The voltage controller is obtainedby a solution of a set of linear matrix inequalities. The voltagecontrol design strategy for each distributed generation (DG) unit isscalable and independent of the other DGs. The effectiveness of theproposed control approach is evaluated through simulation studiesin MATLAB/SimPowerSystems toolbox
