Controllers for interconnected systems with communication delays

Finite-dimensional controllers are developed for interconnected systems, where arbitrary time delays occur in the transmission loops. Various cascade or feedback interconnections are considered, with time delay terms appearing in numerator or denominator matrices of the transfer-functions of the plants to be controlled. The proposed designs achieve low-order and integral-action controllers. The methods are applied to load frequency control of single-area and multi-area interconnections of power systems.