A Low-Cost High-Accuracy Online Electrochemical Impedance Spectroscopy Measurement Strategy for Fuel Cell Electric Vehicle Application

Abstract

This article proposes an improved online electrochemical impedance spectroscopy (EIS) measurement strategy for fuel cell electric vehicle (FCEV) applications. A two-phase interleaved boost converter (IBC) is designed to regulate the output power of a proton exchange membrane fuel cell (PEMFC). Then, the alternating disturbance signals are injected into the fuel cell via the controller of the direct current to direct current (dc/dc) converter without any additional equipment. An injection strategy based on bandwidth distinguishment is proposed to determine the frequency and injection position of disturbance signals. Furthermore, a closed-loop control strategy is introduced to stabilize the response signal’s amplitude at the desired value. The perturbations are effectively regulated to satisfy the signal-to-noise ratio requirement of sensors. Hence, a low-cost high-accuracy online EIS measurement solution is realized. The effectiveness of the approach is validated with a 1-kW converter prototype. The experimental results indicate that the proposed approach can achieve impedance detection with a relatively high degree of accuracy. When testing the setting varies, such as relative humidity fluctuation, the observed spectroscopy clearly demonstrates the noticeable variation in the internal electrochemical reaction.