Application of a fuzzy logic based self-tuning PID controller to the control of drum water level of a boiler for a power generating plant

摘要

It is well known that in the design of self-tuning controllers (including PID) it is essential that a mathematical model of the process is available. In the conventional approach, the model parameters are estimated recursively at each sample time interval, and the settings of the controller are then updated based on the estimated parameter values. The major downfall of the conventional approach has been the requirements of an accurate model of the process, and the inability to set meaningful goals for the adaptive mechanism. The fuzzy logic based approach circumvents the shortcomings by deploying a set of heuristic rules and procedures derived from the "deep knowledge" obtained from experienced skilful control engineers' and plant operators' knowledge of the plant operations and plant behaviours and other plant operational records, In this paper, the author described a method of implementing a self-tuning PID controllers using fuzzy logic methodology. The methodology uses fuzzy inference mechanism to adaptively tune the parameters of the PID controller. The controller is applied to regulate the drum water level of a boiler for electric power generating plant.