Abstract: The main steam temperature controlled object has large inertia, long time lag and timevariation in thermal power plant. In order to enhance the economy and safety of thermal power plant, it is usually required that the main steam temperature control system should have higher performance indexes. However, better performance can not be achieved with traditional control methods which use the normal PID cascade control. In order to improve the regulation quality of the PID controller of main steam temperature, a new fuzzy setting method by using the fuzzy rules of mainsteam temperature system was designed, and the relevant structure of the hardware and software design based on MCS89C52 singlechip computer were introduced in this paper. The simulation results show that this model can online modify its controller parameters to maintain the performance indexes of control system approximately invariable when working conditions change. It has practicable significance for engineering application.

Key words: main steam temperature, control system, single-chip computer, fuzzy control, large inertia