Research On PEMFC Stack Temperature Fractional-order Control Strategy And Its Network Delay Characteristics

Research shows that fractional calculus equations describe the mathematical model of complicated control systems more accurately.Compared with the traditional PID controller,the fractional-order PIλDμ controller is applied to the network remote control system,which makes the system have better control effect and delay performance.In this dissertation,the temperature control system of distributed PEMFC stack is studied.The theoretical basis of fractional calculus,the modeling process of PEMFC stack temperature control system,the time delay in network control and the fuzzy matching control are introduced.A fractional-order PIλDμ controller based on fuzzy matching rules and adjustable order is proposed and designed.Perform simulation experiments,the stability,reliable control performance and better time delay characteristics of the system are verified.The system is applied to the temperature control system of PEMFC stack,and good control effect is achieved.The research and design work is as follows:(1)Based on the time-varying fractional calculus theory,a modified Oustaloup fractional operator approximation method combined with fuzzy matching control theory is used to design a PIλDμ controller with adjustable order of arbitrary differential operators.The design complexity of the fractional-order PIλDμ controller is simplified.The coefficients of the fractional-order PIλDμ controller are determined according to the parameter tuning rules.The influence of the adjustable parameters on the control performance of the fractional-order PIλDμcontroller is analyzed.The comparison of the integer-order PIλDμ controller is simulated.The stability and superiority of the fractional-order PIλDμ controller are verified.(2)The designed variable fractional-order PIλDμ controller is applied to the BLDCM speed control system.The simulation model is established by the speed-current dual-feedback PWM speed regulation method.The adjustable fractional-order PIλDμ controller is verified can be get better control results in the variable load speed control system.Based on the working principle of the PEMFC stack and the control system which has the characteristics of load-speed changes simultaneously,the BLDCM water pump with variable fractional-order PIλDμcontroller can be applied to the PEMFC stack temperature control system.The model is built and simulated by Matlab/Simulimk software to analyze whether the performance of temperature control system can meet the design needs.(3)Research the influence of delay in the control system,and the method of parameter tuning in the second-order delay system of fractional-order PIλDμ controller is described.The simplified model of PEMFC stack temperature control system is taken as the control object.The effects of fixed delay and random delay on the control effect are studied.In Matlab/Simulink software,fixed delay module and random delay module are used in two kinds of controllers verify that the fractional-order PIλDμ controller designed in this dissertation has better delay characteristics.