Hydrogen production through alkaline water electrolysis has emerged as a crucial method for utilizing surplus renewable energy sources. However, the conventional electrolyzer model exhibits limitations in practical applications. In this paper, a simplified and improved model, better suited across a wide range, is established based on the measured data of a 20 kW hydrogen production facility. In addition, a simulation model of a Phase-Shifted Full-Bridge (PSFB) converter with clamping diode is established to verify the feasibility of the proposed theoretical model.