  This work deals with the design of a robust and decentralized passivity-based
control scheme for regulating the voltage of a DC microgrid through boost
converters. A Krasovskii-type storage function is proposed and a (local)
passivity property for DC microgrids comprising unknown 'ZIP' (constant
impedance 'Z', constant current 'I' and constant power 'P') loads is
established. More precisely, the input port-variable of the corresponding
passive map is equal to the first-time derivative of the control input. Then,
the integrated input port-variable is used to shape the closed loop storage
function such that it has a minimum at the desired equilibrium point.
Convergence to the desired equilibrium is theoretically analyzed and the
proposed control scheme is validated through experiments on a real DC
microgrid.
