The dynamic matrix control(DMC) algorithm has long computation time and can not meet the real-time and control performance requirements of thermal control. To solve this problem

an improved DMC algorithm based on multi-rate sampling is proposed

which uses a smaller sampling period in model prediction and feedback correction

and a longer sampling period in rolling optimization. This reduces the prediction and control time domain

reduces the dimension of optimization matrix and greatly reduces the calculation time.Moreover

the improved DMC algorithm is applied to SCR denitration control of a power plant. In MATLAB environment

simulation studies are carried out under three conditions: model matching

control constraints and model mismatch. The simulation results show that

the algorithm has good response characteristics

can quickly overcome the disturbance effects

and has good robustness when the model mismatch occurs. It is suitable for advanced control of power plants' thermal objects.