Simulation tool based on a physics model and an electrical analogy for an alkaline electrolyser

This paper presents an alkaline electrolyser simulation tool (AEST). This new approach is based on a physics model of an electrolytic cell and an electrical analogy of the physical effects taking place in the electrolyser. The physics model has been developed taking into account the electrodes' electrochemical properties, the thermodynamics of the reaction, and the electrical properties of the electrode plates, membrane and electrolyte. The electrical analogy is used to integrate the physics model into the electrical simulation systems. The AEST is able to describe the electrolyser's physical and electrical performance and estimates the operating current as function of the voltage, temperature, pressure and electrolyte concentration. The technical information on the Hydrogen Research Institute (HRI) electrolyser has been used to set up the AEST. The start-up phase of the electrolyser has been analyzed for various operating temperatures, pressures and voltages. The steady-state response of the electrolyser (at constant temperature, pressure and concentration of electrolyte) has been simulated as an element of a possible hybrid system. Simulations have been carried out using MATLAB/Simulink/SimPowerSystems®.