Research And Applicationon On Fractional-order PID And Fractional-order PID-MAC Algorithm

Fractional-order PID is a generalization of traditional PID control. Recently, the concept of fraction is constantly brought in automatical control, signal processing, network communication, electronic engineering, and etc. And it is continue to make substantial contribution for the corresponding fields.Model predictive control is a type of advanced computer optimization control algorithms. It is based on model prediction, rolling optimization with feedback correction and generated directly from industrial process control. The typical algorithms of model predictive control are model algorithmic control (MAC), dynamic matrix control (DMC), generalized predictive control (GPC). They all based on model predictive, rolling optimization and feedback correction.With the characteristics of simple principle, strong robustness, extensive scope, and easy to apply in engineering, traditional feedback control algorithm (PID control) is still one of the most extensive application of conventional control algorithm in industrial process control. However, with the development of industry, objects getting complexity, so that conventional PID control algorithm can not achieve ideal control effect in some practical production process, especially the systems with nonlinear and time varying uncertainty. Compared with traditional integer-order PID controller, fractional-order PID controller has two more adjustable parameters, so fractional-order PID controller can be designed flexibly and its control performance is better. This paper takes Networked Control System and Synchronization generator as examples to analyze the application of fractional-order PID algorithm in engineering practice.Combined with FOPID (Fractional-order PID) and MAC, the new algorithm's derivation is given in this paper. Combined the virtues of the two algorithms, this kind of algorithm is of the advantages of FOPID algorithm, which is reliable in operation and robust in performance, and also of predictive function. Through simulative researches, the influence of FOPID-MAC controller parameters tuning on system performance is analyzed in time domain. And then, FOPID-MAC algorithm and other conventional control algorithms are compared in process control experiment device, takes EPA (Ethernet for Plant Automation) and boiler superheat steam system for examples, which grounds well for engineering application.Finally, according to the characteristic of time delay widespread in industrial processes, the Time-delay Compensation on PIDMAC (TDCPIDMAC) was introduced to improve the control effect. The compensation gene and the transition gene were introduced to adjust the predictive control inputs and the delayed control inputs to realize control stability and speediness. Simulative validation of this new algorithm resulted in improved performance and stability over PIDMAC.