Study and design of a controlled oscillator for an embedded system to measure the complex impedance of PEM fuel cell

摘要

We present in this paper the study and the design of a voltage controlled oscillator (VCO) for an embedded system to diagnose the PEM fuel cell. Some problems related to fuel cells used in the electric vehicle field are the management of its efficiency and the lifetime of its membranes. To do this, the diagnosis using measuring the complex impedance is an important phase. It is based on the injection of a perturbation signal at the output of the PEM fuel cell, then we observe its behavior by measuring its impedance. The used measurement method is the electrochemical impedance spectroscopy (EIS) using the load modulation technique, which is implemented in an embedded measurement system based on a microcontroller. This embedded system needs a controlled oscillator using a frequency spectrum range from 10 mHz to 15 kHz. With this larger frequency bandwidth swiped for measuring the PEM fuel cell complex impedance, this oscillator is a first in the impedance spectroscopy field.