Study and Application of a Practical Method Based Frequency Domain to Decrease the Rank of Model

Model degrading is already a lower-rank approximate model for the high-rank complicate system, and makes it easier and more simply to calculate and analyze the new model than the old system, and this model can supply enough information about the old system. Model degrading is an important link to analyze, design and simulate system. This paper presents a simple and useful method based frequency to decrease the order of model, and gives out the related calculating formula which is proven and simulation results. At last, this method is applied to solve the rank identification in the process of modelling the reheater temperature system of power plants, a prefect result is received. The simulation analysis and real application show its accuracy and effectiveness, it has solved the problem how to construct a model