Research On Multi-Granularity Hybrid Modeling And Co-Simulation Of Digital Electro-Hydraulic Control System For Industrial Steam Turbine

Currently the Differential Equation-Oriented digital simulation method is widely used in the simulation of steam turbine DEH system. It is a process-oriented modeling method which runs simulation tests and performance analysis by establishing the mathematical model of the system to replace the actual system.This method is both poorly intuitive and difficult to understand.In addition to the poor scalability and maintainability,it is unable to get intuitive operating parameters of the key components during the simulation process by using this method.To solve this problem,this paper proposes a Multi-level and Multi-granularity Modular Division Method and a hybrid modeling method by using different modeling methods and softwares to build the model of each module and integrate the models through multi-disciplinary co-simulation technology. After building the integrated model of the system,this paper optimized the controller of the DEH system by using the Fuzzy control strategy.As a result,an excellent control performance is achieved by replacing the traditional PID power controller with the self-tuning fuzzy controller.The main work of the paper includes the following several aspects:1?Multi-granularity module division of steam turbine DEH systemThis paper proposes a Multi-Granularity Hierarchy Modular Division Method after analyzing the structure and the feature of the steam turbine DEH system.The input/output and the interface of the multi-granularity hierarchy model are determined by decomposing the modules objects and building the mathematical models of the each models.The steam turbine DEH system is reasonably divided by the Multi-Granularity Hierarchy Modular Division Method.2?Development of hybrid models of steam turbine DEH system considering the coupling properties of modulesAfter analyzing the merits and drawbacks of two modeling methods of steam turbine DEH system,this paper proposes a new Hybrid Modeling Method based on the moular division method proposed in the previous chapter.After considering the coupling relations between disciplinary subsystems,this chapter uses different modeling methods and softwares to build the mathematical and simulation models of each disciplinary subsystem and model.This chapter also runs simulation tests of key components to verify its performance.3. The optimization of controllers of steam turbine DEH system based on fuzzy controlDue to the complexity of the DEH system and the high requirements of the control quality,This paper optimizes the controller of DEH system by using the Fuzzy control strategy.This chapter improves the original simulation model of the electrical control subsystem by replacing the traditional power controller with a Fuzzy self-tuning PID controller.This improvement achieves better control effects after comparing both the rotating speed output curves and power output curves of the improved DEH system with those of the original one.4?The co-simulation of steam turbine DEH systemBy analyzing the principle of the multi-disciplinary co-simulation of the DEH system this paper runs the co-simulation of the DEH system after integrating the models of the steam,hydraulic and electrical control subsystems and setting up the interfaces and the initial parameters of the models.Eventually,this chapter verifies the accuracy of the system model and the feasibility of the modeling method by comparing the simulation results with the actual situation.