Control Strategy Research for the Combined Air Handling Unit

The interaction of temperature and humidity causes low control performance and high energy cost for combined ABU (air handling unit). So in this thesis a new control strategy combined with decouple and fuzzy theory was studied to improve the comprehensive performance of the combined ABU. Firstly, based on the first principle the dynamics of temperature and humidity were built and transformed into different TFs(transfer function). Then the moisture content was introduced as intermediate variable and feed-forward compensator was designed, the interaction between temperature control and humidity control was decoupled. Finally, a fuzzy controller was designed to adjust the PID parameters adaptively with different operation conditions. The results of case study show that the proposed method is quite effective to the combined AHU, the overshoot and transient time is obviously smaller than conventional control method.