The core components of high-power proton exchange membrane (PEM) electrolysis stacks suffer from severe lifespan attenuation under various complex working conditions

and the AC impedance varies greatly. It is urgently necessary to conduct research on the lifespan diagnosis of PEM stacks with high-power AC impedance as the core criterion. However

the existing high-power impedance excitation schemes have the problem of AC-DC coupling and current shunting

which leads to large measurement errors and makes it difficult to meet the testing requirements. This study proposes a power supply topology architecture for hydrogen production by electrolysis with the ability of high-power online AC impedance excitation. The low-frequency module is composed of a pulse width modulation (PWM) rectifier and a three-phase interleaved parallel Buck circuit

and the high-frequency module is a broadband topology architecture based on supercapacitors. Relevant control strategies are proposed according to the architecture

and a hybrid AC-DC decoupling technology is proposed to effectively improve the accuracy of broadband AC impedance. Finally

a 220 kW engineering prototype is built

which proves the correctness and effectiveness of the proposed architecture.