Engineering Practice of Cascade Control System for Main Steam Temperature Using PSO Optimizing Method

The cascade PID control is a commonly used strategy to control main steam temperature in the engineering field and its control quality depends largely on the parameters tuning. On the basis of practical situation, a method of simultaneously optimizing the parameters of main and secondary PI controllers using PSO(Particle swarm optimization)is proposed in this paper to acquire optimizing control parameter. In addition, three issues, which are the choice of transfer function, judgment of positive and negative PID and determination of objective function, are pointed out respectively when using this kind of method. Simulation results show that the optimized controller can overcome shortcomings of long settling time and frequent action of actuator caused by improper parameters setting in the original control system. Practical operation effects also show the control effect of main steam temperature is improved greatly after parameter optimization.