Research On Main Steam Temperature Control Of Utility Boiler Based On Internal Model Control

The main steam temperature control system is very important for the safety and economy of boiler unit operation, so it is given a higher demand. However, because the object has the properties of nonlinearness, time-variation, large inertia and large time delay, especially in recent years, the tendency of generator unit development is of high parameters and large capacity. The object is getting more complex, and the higher demand of control quality is given. The traditional PID cascade control system can not fully meet control performance requirements of superheated steam.The control theory circle and engineering circle concentrate upon the internal model control because it has the advantages of simple and visual design, good track-regulation performance and eliminating unmeasurable interference. Furthermore, it is suitable for the large time delay system as smith prediction device. Therefore, it is of great practical significance that internal model control is used in main steam control system with the properties of large delay and large inertia.The paper designed a new internal model cascade control system on the basis of deep analysis of internal model cascade control strategy and was innovatively applied to maintain steam temperature control after improvement. The mathematic model of main steam temperature was established by using large amount of field data of Heilongjiang Hegang power plant and quantum neural networks. This is a method of converting the network weight values to transfer function form after training and testing network. The filter parameter in the internal model controller was optimized by using quantum particle swarm optimization. Finally, internal model-P cascade control system was composed with combining internal model control algorithm. Simulation results show that quantum neural network internal model cascade control system has strong resistance to disturbance, robustness, good regulation quality and control effect for utility boiler main steam temperature significantly better than PID-P control system.