Reduced-Order Observer and Controller Design for A 1000MW Ultra-Supercritical Unit

摘要

Recently due to the increase in electric power generated by wind and its feeding into the power network, even 1000MW ultra-supercritical units are required to operate in variable load conditions. This puts forward higher requirement in controlling of 1000MW ultra-supercritical units. Unfortunately, the complexity of dynamic models of 1000MW ultra-supercritical units makes it difficult to design controllers for those units using existing popular control tools. In this paper, we focus on designing a reduced-order observer as well as an exponentially stable controller in order to enhance the control performance of the ultra-supercritical unit, comparing with a constant controller. The reduced-order observer is first designed to estimate the amount of coal coming into the boiler for combustion. As a matter of fact, such amount of coal plays an important role in controlling the unit and it is really challenging to measure the amount of coal due to the limitation of sensors and the complex working conditions of boiler. It reveals that the reduced-order observer can rapidly estimate the true amount of coal. Furthermore, an exponentially stable controller is constructed in a straightforward way. This exponentially stable controller takes the estimated amount of coal from the reduced-order observer into account sufficiently. The computer simulations are conducted and the results suggest that the performance of the unit can be enhanced under the exponentially stable controller compared to the constant controller.