The multivariable decoupling internal model control(IMC)method was employed to design the unit coordinated control system with strong coupling

great inertia and large time delays.By constructing the desired closed-loop transfer function matrix

the prediction and right half plane pole produced by the inversion of the model were compensated.Then the stable and realizable P-norm decoupling internal model controller can be designed.This controller has simple design method

good decoupling effect and its parameter is easy to regulate.Taking a 660 MW unit as the object

this decoupling IMC design method was applied in the simplified load-pressure dynamic model.Moreover

the anti-interference of the control system and robustness of model mismatch were verified.The simulation results show that

the decoupling IMC based coordinated control system accelerates the load response speed and reduces the dynamic deviation of the main steam pressure.