Active Disturbance Rejection Controller Tuning And Its Applications To Thermal Processes

With the development of thermal power systems in modern industry, the controlquality become more and more important. Since the nonlinearity, time varying, time-delay, disturbance and coupling in thermal power systems are increasingly remarkable,the classical PID controllers, which are wildly used in practice, can not meet the re-quest of production. Therefore, people have been working on searching better controltechnologies, and Active Disturbance Rejection Control (ADRC) is an alternative.In this thesis, a novel tuning method for ADRC is presented. It can handle moreuncertainties in the processes than the existent method and still keeps its simplicity.Here, only one parameter is tuned with the assumption that the desired settling time isgiven. The method is tuned and tested against a variety of unknown processes of vari-ous orders, stability characteristics, and time- delays. Simulation results show that theADRC is a good, general purpose, alternative to PID that o?ers significant performanceand robustness advantages.Then, based on design methods above, for four transfer function models of di?er-ent loads in superheated steam temperature control system, the ADRC cascade controlis discussed. Here, the ADRC tuning procedure is demonstrated in details for practi-tioners. Simulation results show that, the ADRC can achieved better performance thanthe Internal Model Control, especially when disturbance existed, at each load. Further-more, the ADRC can achieved more robustness by simple adjustment if needed, suchthat all the four models of di?erent loads can be controlled by one ADRC controller.This ADRC cascade control can be used in other cascade systems as well.Finally, a preliminary study on combustion oscillation ADRC control is discussed.Here, the producing and control mechanism of combustion oscillation is introduced.For a nonlinear model of combustion oscillations, the simple phase-shift controllerand ADRC controller was designed and further analyzed. The analysis and simulationresults both indicated that the ADRC can eliminate combustion oscillations at design conditions. Furthermore, the ADRC is robust at o?-design conditions.The study of this thesis demonstrates the promising future of ADRC in the controlof thermal processes.