H-INFINITY CONTROLLER-DESIGN FOR BOILERS

This paper examines the ability of the H-infinity design methodology to provide a solution to a gas- or oil-fired boiler control problem, and address the nontrivial application issues of the H-infinity design. The H-infinity methodology is applied to an experimentally verified heating-congeneration boiler model which exhibits nonlinearities, instability, time delays, non-minimum phase behaviour, and coloured noise disturbances with sensor noise in the frequency range of the significant plant dynamics. The design shows that, to satisfy performance criteria, a high order controller is needed. The paper also demonstrates a trade-off between the reduction of controller order and the loss of controller performance.