Converter-Based Online EIS Measurement of FC Stack Using Binary Multi-Frequency Signals

Electrochemical impedance spectroscopy (EIS) testing is a key technical tool to evaluate the health of fuel cells. In recent years, the online EIS measurement method based on a DC/DC converter has gradually become a research focus due to its advantages of no interruption of system operation and low cost. However, how to further improve the efficiency and accuracy of online EIS measurement is still an urgent problem. To this end, this paper proposes the use of a binary multi-frequency signal (BMFS) as an excitation signal. It has two advantages: firstly, it possesses multi-frequency component characteristics; secondly, it ensures a high energy distribution for each frequency component. These features significantly improve the interference resistance in noisy environments, thereby achieving high-precision online measurements of EIS. To verify the effectiveness of the proposed method, a simulation model is constructed on the MATLAB/Simulink platform, and the experimental results prove the feasibility of the method.