Unit Load Control System Based on Multivariable Feed-Forward and Feedback GPC

Abstract

Unit load system of thermal power plant is a multivariable system with strong coupling. Its performance has great impact on the safety and economy of the unit. In this paper, multivariable feed-forward and feedback GPC (generalized predictive control) is introduced into the control of unit load system. The coupling between the power loop and pressure loop is treated as knowable exterior disturbance and considered during the designing process of GPC controllers. With structure analysis, the new controller is equivalent to feed-forward and feedback control system. But the new GPC controller has the merits of rolling optimization and without tuning parameters. Simulation of 125 MW unit load system proved that the new method could meet the requirements of quick load response ability and maintaining the stability of steam pressure. The robustness of the new method is also satisfactory