PEM-electrolyzer modelling and control strategies in the extended node method for hybrid power system modelling

In a future renewable energy system, electrolyzer, as coupling elements between power and gas systems, convert renewable electricity into storable hydrogen, which can be used in further consumption sectors. The general scope of this investigation is a controlled proton exchange membrane electrolyzer at a low voltage grid. For this, the proton exchange membrane electrolyzer as well as the power electronics for grid connection are developed as components for the "Extended Node Method" based on electrical equivalent circuit diagrams. It is shown how these components are especially defined for this method, how their topology affects the node definitions and how the AC/DC and DC/DC transitions are realized. As a study case, a sample model of a 40 kW stack is considered. The setpoints for electrolyzer current as well as reactive power are adjusted and transient calculations are carried out. The results are compared with models in Simulink/Simscape and show general agreement.