Hydrogen Flow Rate Control of a Proton Exchange Membrane Electrolyzer

The purpose of this paper is to develop a robust hydrogen flow rate control of a proton exchange membrane (PEM) electrolyzer. In this work, a quadratic DC-DC step-down converter is used to interface the DC grid and the PEM electrolyzer since it has an improved voltage ratio compared to the basic step-down converter. The hydrogen flow rate is controlled through the current at the output of the quadratic DC-DC converter. Besides, the hydrogen flow rate strongly depends on the state of charge of hydrogen storage and hydrogen consumption from the fuel cell and consequently, its reference may change during operation. For this reason, to cope with the change of hydrogen flow rate reference, a sliding mode control has been developed. Hence, the controller can ensure good performance when sudden load variations appear. An experimental test bench has been developed with a PEM electrolyzer emulator and the obtained results demonstrate the effectiveness of the developed control strategy.