Inlet gas flow, pressure and temperature control technology for PEMFC stack testing platforms

This study proposes a novel integrated control method for the fuel cell stack testing platform, addressing the precise regulation of inlet gas flow, pressure, and temperature. After identifying the system model at equilibrium operating conditions, inlet gas flow and pressure control methods are developed based on internal model control. For inlet gas temperature control, a Pulse Width Modulation (PWM) generation module is designed to convert the continuous PI controller output into a Boolean signal for solid-state relay operation. To validate the proposed control methods, simulations are conducted in MATLAB/Simulink®, followed by experimental verification on a fuel cell stack testing platform. The experiments include a constant-pressure inlet flow step tracking test, a constant-flow inlet pressure step tracking test, a simultaneous large-step flow and pressure tracking test, a robustness test of temperature control under gas flow disturbances, and a 15-h stability assessment at a constant flow rate. The results indicate that steady-state errors remain below 1NLPM for flow control and 1 kPa for pressure control, while the maximum absolute error in inlet air temperature is only 0.7 °C. These findings confirm that the proposed control techniques effectively meet the high dynamic and precision requirements of the testing platform.