基于模糊天牛须PID的稀土电解温度浓度解耦控制

Temperature and Concentration Decoupling Control of Rare Earth Electrolysis Based on Fuzzy PID

稀土电解过程中电解槽内温度是影响出料金属品质、电解能耗的关键条件,同时槽内氧化物浓度决定了出料金属的效率和电解过程的稳定性。但实际电解槽内化学反应多、过程复杂,电解槽温度、熔盐氧化物浓度两者存在非线性的耦合关系。电解槽模型具有高滞后、强耦合、时变系统的特点,单独以电解温度或氧化物浓度作为被控变量难以保证出料金属的品质。以6 kA氧化钕电解温度、氧化物浓度作为输入,阴极电流密度、氧化物下料率作为输出,对输出变量进行解耦补偿,实现多变量解耦控制,从而提高氧化钕电解的品质;通过模糊PID控制器引入专家知识库对温度、浓度实现有效控制,改善了以往稀土电解过程中控制变量单一效果不理想的难题;借助天牛须的寻优迭代能力优化模糊PID的初始参数。利用Simulink平台对模糊PID解耦控制器和常规PID控制器进行仿真对比实验,实验结果表明:模糊PID解耦控制系统较单一温度PID控制效果更好,超调量提高了6%,系统响应速度提高25%。

The temperature in the electrolytic cell is the key condition that affects the quality of the metal and the energy consumption in the electrolytic process,and the oxide concentration in the cell determines the efficiency of the metal and the stability of the electrolytic process.However,there are many chemical reactions and complicated processes in the actual electrolytic cell,and the temperature of the cell and the concentration of molten salt oxide have nonlinear coupling relations.The electrolytic cell model has the characteristics of high hysteresis,strong coupling and time-varying system,and it is difficult to ensure the quality of the discharge metal with electrolytic temperature or oxide concentration as the controlled variable alone.The electrolytic temperature and oxide concentration of 6 kA neodymium oxide are taken as inputs,and the cathode current density and oxide feeding rate are taken as outputs to decouple the output variables and achieve multi-variable decoupling control.Thus improving the quality of neodymium oxide electrolysis.The expert knowledge base is introduced into the fuzzy PID controller to realize effective control of temperature and concentration,which improves the problem that the single effect of control variables in the previous rare earth electrolysis process is not ideal.The initial parameters of fuzzy PID are optimized by means of the optimization iteration ability of the Longox whisker.Simulink platform is used to simulate and compare the fuzzy PID decoupling controller and the conventional PID controller.The experimental results show that the fuzzy PID decoupling control system is better than the single temperature PID control,the overshoot is increased by 6%,and the system response speed is increased by 25%.