Fuel Cell Condition Monitoring System Based on Interconnected DC–DC Converter and Voltage Monitor

This paper presents a comprehensive solution for condition monitoring (CM) of proton exchange membrane (PEM) fuel cell systems. It comprises a modular dc-dc converter, a 90-channel fuel cell voltage monitor, and embedded diagnostics algorithms. Besides providing its basic functionality, the dc-dc converter is designed to perform diagnostic probing of fuel cells by injecting current excitation waveforms. The designed voltage monitor enables the precise voltage measurement of all individual cells in the stack. The interconnection between the dc-dc converter and the voltage monitor provides a platform for an embedded CM system. It employs a novel algorithm for fast electrochemical impedance estimation and automatic tuning of the thresholds used in the fault detection algorithm. The final output is a unit-free condition indicator that describes the overall condition of the fuel cell stack. As such, the designed CM system allows the seamless integration and optimal exploitation of fuel cell power systems. The complete solution has been evaluated on an 8.5-kW PEM fuel cell power system.