Passive Controller Design of Mass Exchanger Network

Abstract

This work mainly focuses on applying the passivity concept to a mass exchanger network. Development of the mass exchanger state space model with controller design is proposed. The state space equations of the mass exchanger model have been developed based on assumptions a of lumped parameter system, including well mixing rich and lean streams, a linear equilibrium relation over the operating range and isothermal and isobaric conditions. The mass exchanger model is characterized as a non-passive system due to its positive passivity index, and according a weighting function is introduced to shift the system to passive region along with the controller tuning. A case study of a five-streams mass exchanger network with four control loops is demonstrated using a weihing function to again counter the non-passive characterstic. Multi-loop passive PI controllers of the mass exchanger network are developed. This passive control configuration is tested by both disturbance rejection and set-point tracking. The designed passive controllers are able to completely eliminate the impact of disturbance effects, and all control loops show good performance to track 4, 15, 3 and 1.5% change of the set-points.