Price-driven Coordination for Solving Plant-wide Mpc Problems

Two-level model predictive control (MPC) is the dominant multivariable control technology in the process industries. In large-scale MPC applications, such as plant-wide control, two common approaches are centralized and decentralized MPC schemes, which represent the two extremes in the “trade-off” among the desired characteristics of an implemented MPC system. Alternatively the coordination of decentralized MPC systems may offer the best attributes of each of the extremes. The price-driven coordination scheme requires the existence of “equilibrium prices” and has extensive large-scale applications in economic planning. On-line solutions to large-scale optimization problems require an efficient price-adjustment method. As the coordination problem for decentralized MPC falls into the category of limited resource case, this work develops an efficient priceadjustment algorithm by using Newton’s method, in which sensitivity analysis and active set change identification techniques are employed. The proposed priceadjustment strategy is incorporated into a coordinated, decentralized MPC scheme that shows a high degree of accuracy, while retaining the reliability of original decentralized scheme at a reasonable computational load. Copyright c ©2005 IFAC