Coordinated control of circulating fluidized bed boiler based on the fuzzy PID control

In this paper, a new sequential relay feedback method for the tuning of decentralized PID controllers in intelligent coordinated control systems (CCS). Based on the specified phase and gain margin, the parameters of the fuzzy self-adjusting PID controllers and the fuzzy gain scheduling PID controllers are determined. The scheme is implemented through the function code in typical DCSs (EDPF-NT, XDPS, etc). It has been used for control of the 300MW circulating fluidized bed (CFB) units. The industrial applications show that the scheme achieves better performance in the specific range of load variations.