Real Time Control of Inverse Response using Dynamic Matrix Control

A DMC algorithm was used to control a column temperature exhibiting inverse response dynamics to heat input. The DMC algorithm was used for feedforward control on column through-put disturbance. The control application also used DMC to dynamically predict the heat input effect on the bottoms temperature which had a high constraint limit. A system identification software package was used after traditional control techniques were not successful. The package diagnosed the unexpected inverse response and isolated column throughput as the key disturbance to column temperature profile. The DMC controller service factor has consistently been above 99%. Column temperature control has been improved substantially, resulting in improved quality while increasing column capacity.