Research On Hybrid Modeling Method Of The Superheated Steam Temperature System

In this paper, the methods that combines mechanism model with parameter identification is applied for establishing composite super-heated steam temperature system model. According to the composition of super-heated steam temperature system, spray desuperheater and super-heater are studied. Build the object model transfer function expression through the mechanism analysis to determine the model structure, order and model parameter expression, this composite model framework is built on the basis of all above.In the modeling process, determination of the model structure and model order is most critical, as the key to model quality, it ensures the output characteristics of the model.In the identification of transfer function model parameter, the input and output data are required to fluctuate in a small range of stable operating conditions.After determine the process variables that based on mechanism model need to be collected in the field, the main steam flow, the primary air flow and the main steam pressure parameters of the boiler are used as the steady state variables. carry out steady field data extraction by sliding window detection method, filter out the data sections that meet the identification demand, a series of pre-process are required based on the actual characteristics of data.Determine the initial value of the composite model according to process parameters under the 60%,80%,100% three typical conditions and specific function expression, correct unknown portions of the composite model and model parameters coefficient by model output and the principle of actual output of the process minimization to obtain specific forms of super-heated steam temperature system transfer function model under different conditions. simulate and verify composite model according to actual operating data to confirming the accuracy of the model.