Dynamic Emulation of a PEM Electrolyzer by Time Constant Based Exponential Model

Abstract

The main objective of this paper is to develop a dynamic emulator of a proton exchange membrane (PEM) electrolyzer (EL) through an equivalent electrical model. Experimental investigations have highlighted the capacitive effect of EL when subjecting to dynamic current profiles, which so far has not been reported in the literature. Thanks to a thorough experimental study, the electrical domain of a PEM EL composed of 3 cells has been modeled under dynamic operating conditions. The dynamic emulator is based on an equivalent electrical scheme that takes into consideration the dynamic behavior of the EL in cases of sudden variation in the supply current. The model parameters were identified for a suitable current interval to consider them as constant and then tested with experimental data. The obtained results through the developed dynamic emulator have demonstrated its ability to accurately replicate the dynamic behavior of a PEM EL.

Energy Efficiency Based Control Strategy of a Three-Level Interleaved DC-DC Buck Converter Supplying a Proton Exchange Membrane Electrolyzer

“…Compared to previous works reported in references [16,17] introducing the studied converter, the main objective of this work is to develop a suitable PI controller of the three-level interleaved DC-DC buck converter connected to a PEM EL emulator. This emulator is realized through an equivalent electrical circuit developed in a previous research work [20]; able to accurately replicate the dynamic operation of the EL. Since the developed controller is based on the PEM EL voltage, thorough investigations have been carried out on energy efficiency of the system, hydrogen flow rate, and specific energy consumption.…”

“…By comparison, energy efficiency takes into account additional losses such as membrane losses and heat losses both in the anode and cathode. These losses have been modeled as resistors in an equivalent electrical model proposed in reference [20]. As it can be observed in Figure 3, when the PEM EL operates at a current value higher than 10 A (i.e., 0.2 A•cm −2 ), the stack voltage drops.…”

“…By comparison, energy efficiency takes into account additional losses such as membrane losses and heat losses both in the anode and cathode. These losses have been modeled as resistors in an equivalent electrical model proposed in reference [20].…”

“…It is important to point out that the parameters of this equivalent electrical model may change according to the operation of the EL. Indeed, as highlighted in reference [20], according to the input current range operation, the dynamic behavior is modified. The parameter V int strongly depends on gas pressures and temperature as well; whereas the resistances of the model depend on the input current since the time constants change.…”

“…The parameter V int strongly depends on gas pressures and temperature as well; whereas the resistances of the model depend on the input current since the time constants change. However, the determined parameters in a previous work allow accurately modeling the behavior of the PEM EL for the studied current range [20].…”