Thermal Optimization Of The Automatic Control System Pid Parameters Tuning Its Application

With the development of the power industry, the safety and economy of the boiler turbine generator units become more and more important. The performance of the control systems of units directly influences the safety and economy of units. For fixed structure control system, its performance depends on the adjustment of controller parameters.At present, the PID controller is widely used in thermal processes control in power plants. This dissertation studies on the problem of the PID parameters optimal adjustment according to the character of thermal processes. The main content include:1. The identification methods of transfer function are studied for three kinds of typical thermal processes. The related identification soft is developed. Simulations are carried out to show that the developed soft is valid.2. The PID parameters adjustment methods are studied for single loop- control sy stems ^ cascade control systems , feed forward back forward control systems and 2*2 multivariable control systems according to the character of thermal processes control. The optimal adjustment strategy of using simple shape algorithm to search the optimal PID parameters with the initial PID parameter values obtained by related adjustment methods is proposed. The optimal adjustment soft is developed also. Simulations for 2*2 multivariable control systems parameter adjustment are carried out. The results show that the proposed optimal adjustment strategy and the related soft are valid.3. The application study is carried out for the PID parameter optimal adjustment for the boiler steam temperature control system of a power plant. First, the step response of the steam temperature process is obtained by experimentation, and the transfer function of the controlled process is calculated out using the step response data of the process. Then, the PID parameters of the control system are optimized using the obtained process transfer function. Finally, simulations are carried out to show the performance of the optimization-before system and optimization-after system. The results provide reliable guarantee for the optimization results to be used in real control system.