Fuzzy PID Control For The Main Steam Temperature Of Power Station Boiler

The main steam temperature system has the properties of large capacity and large time delay. When the temperature is beyond the prescribed scope, the equipment will damage more easily. Especially in the recent years, the unit in the power station is getting more complex, and control quality demands more highly. The main steam temperature is the important indicator for the safety and economy in the power station. It is difficult to use the PID control system to make the steam steady. So we use the cascade control system with the signal which responds erlier than the main steam temperature. The control system will react quickly when the disturbance occurs. At the same time, we use the thought of multiple model control under different conditions and scheduling control for reference to design a T-S fuzzy PID controller, which can get the main steam temperature steady when working condition changes. This design includes the following two aspects:(1) Local controller design: We have to get the local controllers to maintain the main steam temperature steady in different working stations. In this paper, we get the parameters of PID controllers of inner and outer loop in typical mode of operation based on PSO with mixed index of H2/H∞. It is easily to be achieved for scientific studies and engineering applications. It is not rely on the specific form of the controlled plant and strong robust.(2) The integration of global controller: After the local controllers are designed, we use the membership functions to design the global controller to adapt to a wide range of variable working conditions. The global controller usesdifferent local controllers to make the control fit for the korking stations. It can ensure the local controllers a smooth transition.We get the simulation test in the typical woking stations and varingt woking stations. The results show that this system has a good dynamic performance and load adaptability.