Automatic control technology;  PID control;  boilers;  Main steam temperature;  Mathematical model

A quasi-linear mathematical model of thermal process objects is proposed, the relationship between PID controller parameters and thermal object model parameters under variable working conditions is derived, and a new PID parameter adjustment algorithm is established. The gain function can be obtained according to the theoretical analysis of the thermal process or the statistical analysis of the steady-state working condition data, and the relationship between the differential time function and the integral time function can be determined according to the principle of non-oscillation inside the controller, which can reduce the PID online adjustment parameters from 3 to 1, simplifying the field tuning algorithm. Aiming at the boiler main steam temperature control object, an online PID parameter adjustment algorithm based on dynamic overshoot is proposed, which can improve the quality of boiler main steam temperature control, and is verified by example.