Multi-Objective Regulation and Protection Control for Ship Steam Power Equipment
|School||Harbin Institute of Technology|
|Course||Power Machinery and Engineering|
|Keywords||Ship steam power equipment DEB switching control advance and reverse coordinated control|
Ship steam power equipment is one of the most important equipments of ship. when it was running, the loads varied frequently, and the varying range is big. So it required a high response performance for the system. Furthermore, the boiler-turbine control is one difficulty of the steam power equipment control. Because the characters of nonlinear, strong coupling, time-vary and big delay, routine control strategy can’t satisfy the requirements of the system. It is important for both to be coordinated better during the operation of the boiler and the turbine, especially off-design working condition. Based on the analysis of the dynamic characters of the boiler-turbine system, this dissertation researched the mathematic modeling and control of the coordinated system.First, establish the nonlinear model of the boiler-turbine by it’s complex thermodynamic process which include improving the existed thermodynamic model of the boiler and establishing the Digital Electro-Hydraulic control of model. In nature, it is a two-input and two-output of the nonlinear characteristics model. Then we do a series of simulation calculation using this model, and validate the correctness of the model from the side of physics. Analyze the model characteristic, research its control law, and design the controller system are on the basis of the nonlinear components model. The components model also the basis to establish real-time model and expansion the research of performance parameters.Based on analyzing two basic schemes—boiler followed turbine and turbine followed boiler in the traditional boiler-turbine control system, this dissertation expatiated the principle of coordinated control system and given its structure diagram. Then we use the control strategy of boiler followed turbine. The DEB (Direct Energy Balance) control scheme, which is now widely in practice, is able to realize the thought of Gain Scheduling and Static decoupling, partially neutralize the nonlinearity of the system Then we give dynamic response of every parameter in the small and big loads varying.The paper considered the control problems of ship steam power equipment and the contradiction between the high maneuverability and safety due to the big loads varying frequently. The paper analyzed the control tasks, safe boundaries during working, the boiler-turbine working conditions. And the paper expounded the multi-objective control problem is a multi-model control problem, and proposed the multi-loop control system in structure, and according to the Max/Min switching strategy to control. Then we design the PI control system. Based on this switching strategy, analyze the problem of switching strategy and give the solution of the problem. Finally, we validate the correctness of the model by simulation calculation.Moreover, according to the properties of ship main turbine it has reverse turbine. In order to meet the combination of control strategy on the safety and flexibility, we propose a feasible solution to advance and reverse conditions. Finally, we validate the correctness of the model by simulation calculation.