An embedded DSP-based Frequency Response Analyzer for Fuel Cells Monitoring and Characterization

This paper presents an embedded frequency response analyzer (EFRA) for fuel cells (FC) based on a low-cost digital signal processor (DSP). Frequency response analysis technique provides valuable information of different electrochemical processes that occur inside the FC. The small size and low power consumption allows this special device to be embedded into the FC controller or the power conditioning stage. The system is capable of measuring automatically the frequency response of the FC at different operating points, even when the FC is operating with load. These measurements can be used to characterize the FC at design stage and to perform on-line monitoring of the FC state during continuous operation. The proposed instrument uses the lock-in amplification technique, which allows very accurate and precise measurements even in the presence of high noise levels. The proposed hardware and signal processing technique are described in this paper including experimental result of a 1.2 kW proton exchange membrane fuel cell (PEMFC) system