Flow Control of Fuel Cell Centrifugal Compressor Based on Sliding Mode Variable Structure

Air compressor is the key component in the proton exchange membrane fuel cell (PEMFC) system which utilizes the electrochemical reaction of the hydrogen and oxygen to produce electricity. Compressed air (including 21% oxygen) provided by the compressor has to be supplied to the cathode of PEMFC. The mass flow and pressure of the supplied air directly influence the output performance, i.e., the V-I characteristics, as well as the safety of the fuel cell. Insufficient air flow may lead to the “oxygen starvation” phenomenon which reduces the fuel cell lifespan and could damage the membrane in the sever case. In order to satisfy the fuel cell requirement, a sliding model controller is developed in this paper to control the mass flow. A super-twisting method is used to control the compressor driving torque and thereby the mass flow dynamics. The proposed method is validated by the simulation results.