Filter Cancellation Technique for PEMFC Impedance Evaluation

Abstract

Scientists around the world regard fuel cells as a promise solution to the fossil fuel mitigation. However, PEMFC needs a proper electric power converter to convert their dc voltage output to match the conventional dc or ac electric load. To design the proper electric power converter, the characteristic of the targeted PEMFC like the characteristic curve or the cell impedance is required. The equipment for measuring the electrochemical impedance, which is usually available in chemical or material science laboratory, is not suited for evaluating the fuel cell system at the rated operating point. The limit is mainly on the current rating of the measuring equipment. This forces the electric converter designers to evaluate the cell impedance manually. This paper presents several pitfalls and solutions in evaluating the cell impedance. With proper measuring configuration presented in this paper the cell impedance can be extracted from the measured signals without using any high-end equipment.