Implementation and optimization of perturbation currents for vehicular proton exchange membrane fuel cells online electrochemical impedance spectroscopy measurements

This paper presents an implementation method of perturbation currents for vehicular proton exchange membrane fuel cell (PEMFC) online electrochemical impedance spectroscopy (EIS) measurements. The topology of the parallel dual‐boost DC/DC converter system for the EIS measurement is presented. The DCdc and DCac modules in the converter system implement the DC current and the sinusoidal EIS perturbation current independently. Simulation results show that the proposed perturbation current generation method can be implemented efficiently. In the frequency domain, the current of DCdc couples to the perturbation current of DCac, leading to a reduction in the accuracy of the current amplitude after superposition. The mechanism of current amplitude reduction after superposition is discussed. Feed‐forward compensation and fuzzy compensation optimization are proposed for the DCdc current control. Both compensation algorithms achieve excellent results. A comprehensive framework for evaluating the compensation effect is presented. The evaluation results show that feed‐forward compensation has a better advantage in solving the above problems due to its simplicity and less impact on hardware control. Experimental results show that with the optimization algorithm, the input perturbation current increases from 6% to 83% of the theoretical value.