Research On Advanced Control Algorithms For HTR-PM

There is a growing demand of abundant clean and alternative energy for the problem of energy depletion and environmental pollution. High temperature reactor is likely to be the fourth-generation nuclear reactor for its security nature. Our country is now strongly supporting the research. HTR-PM reactor is a reactor designed by Tsinghua University, based on pebble bed modular technology with a structure of "Two reactor with one turbine". Its features differ greatly from the popular reactor like PWR and BWR. It is hard to control smoothly with the special features of strong nonlinearity and longtime delay. The thesis has a systematical research on control methods of a wide range of load change of HTR-PM.The main research work of the thesis is listed as follows:1. Build and improve HTR-PM semi-physical simulation platform, develop a communication interface based on OPC standard between advanced control software and semi-physical simulation platform to make the platform suitable for experimental operation. Analyze the pros and cons of current PID control algorithm and design an identification test to obtain linear models of different operation points. Use gap metric method to evaluate model nonlinearity of different operation points. Design a control scheme based on linear MPC algorithm and have a control simulation of a wide range of load change on the semi-physical simulation platform.2. For strong nonlinear characteristics of a wide range of load change, I provide a nonlinear model predicative control algorithm based on mechanism model with an online aggregation strategy. Using DAEs of HTR-PM as a mechanism model, discretizing the model based on finite element orthogonal collocation method, we transform solving a DAEs problem to solving a NLP problem and solve it using interior point method. Due to the huge scale of model after discretion of the DAEs, an online aggregation strategy is used to reduce computing scale and accelerate solving.3. For computation delay problem of model predicative control based on mechanism model, a method with two layer of "first rough then exact" optimization control algorithm is proposed. Take a test of large range of load change both on CSTR and HTR-PM plant. Validate the conclusion that the algorithm has the same stability as the INMPC and it can decrease the solving time by 40%.Finally, a summary of this thesis was given and future research prospect was discussed.