This paper presents a solution of implementation of electrochemical impedance spectroscopy (EIS) functionality in the power converter used for Proton Exchange Membrane Fuel Cell (PEMFC) power management. The fuel cell is electrically coupled to an electric vehicle DC bus using a DC/AC/DC converter based on an inverter stage, a high frequency power transformer stage, and a rectifier stage. The EIS is achieved by the power converter in order to be performed without additional hardware, cost and volume. The proposed EIS process is integrated in the power control to allow real time using of EIS results for embedded diagnosis or control improvement. An experimental platform developed in the laboratory has validated the online EIS method on a 750 W 20-cell-stack. Experimental validation tests presented in this paper illustrate spectral impedance monitoring for variations of requested current, air humidification rate and hydrogen flow rate. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.