Control of power-plant main steam pressure and power output based on fuzzy reasoning and auto-tuning

This paper presents the new development of the boiler-turbine coordinated control system using fuzzy reasoning and auto-tuning techniques. The boiler-turbine system is a very complex process which is a multivariable, nonlinear, slowly time-varying plant with large settling time and a lot of uncertainties. A special subclass of fuzzy inference systems, called the GPE(Gaussian partition with evenly spaced midpoints) systems, is used to self-tune the main steam pressure PID controller's parameters on-line based on the error signal and its first difference, aimed at overcoming the uncertainties due to changing fuel calorific value, machine wear, contamination of the boiler heating surfaces and plant modeling errors. For the large variation of operating condition, a supervisory control level has been developed by auto-tuning technique. Satisfactory industrial application results show that such a control system has enhanced adaptability and robustness to the complex process, and better control performance and high economic benefit has been obtained.