Application of multivariable H∞ suboptimal control for proton exchange membrane fuel cell pressure control system

To overcome the influence of nonlinearities and the inconvenience of solving Riccati algebraic equation, a multivariable H∞ suboptimal control method based on linear matrix inequality(LMI) was proposed to directly control a dynamic model of proton exchange membrane fuel cell (PEMFC) pressure system. According to the nonlinear coordinate transformation and the dynamic extended approach, a Brunovsky canonical form was obtained and then the nonlinear control law combined with H∞ suboptimal control strategy to solve a convex restricted problem might be obtained. The comparison between simulation results and experimental results demonstrated the validity of the proposed dynamic nonlinear model. By simulating the vehicle running process, it was verified that the proposed nonlinear suboptimal controller could maintain the hydrogen partial pressure steady and oxygen partial pressure steady, decrease the pressure deviation between anode and cathode, prevent the membrane damage, and guarantee stable operation of the system under the large disturbances. Simultaneously, the comprehensive comparison with other control methods proved the superiority and validity of the proposed method. Furthermore, the structure singular value μ analysis method was utilized to testify the robust stability. Therefore, the proposed control method will make important effect for investigating the nonlinear control of PEMFC system. © 2010 Chin.Soc.for Elec.Eng.