Fuel Cell Stack Fault Diagnosis Using Summed Frequency Current Injection
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Solution Overview
Problem
Current fuel cell stack monitoring systems, such as cell voltage monitoring apparatus and electrochemical impedance spectroscopy, are complex, expensive, and inefficient for real-time fault detection and maintenance, particularly in fuel cell vehicles, as they fail to accurately identify fault causes and require lengthy testing times.
Innovation Solution
A method and apparatus that generate an injected current by summing alternating currents of different frequencies, using band pass filters to extract specific frequency currents for calculating total harmonic distortion and impedance, and applying these currents to the fuel cell stack to diagnose faults in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cell voltage monitoring apparatus directly monitors voltages of all cells using a complicated circuit configuration, then fault cell position can be monitored, but the apparatus becomes expensive and difficult to assemble and maintain
Solution Approach 1:
The patent extracts only the essential monitoring function by measuring voltage at strategic points (first and second voltages at different locations) rather than monitoring all cells directly. This extraction of key measurement points simplifies the circuit configuration while maintaining fault detection capability through voltage difference analysis.
Solution Approach 2:
The patent introduces voltage difference calculation as an intermediary step between raw voltage measurements and fault diagnosis. By calculating the difference between first and second voltages, the system indirectly detects faults without requiring direct monitoring of every cell, thus reducing circuit complexity while preserving measurement precision.
2Measurement precision
If electrochemical impedance spectroscopy is used for fault detection, then detailed electrode reaction information can be obtained, but the testing time becomes excessively long
Solution Approach 1:
The patent applies periodic alternating current at specific frequencies (including 1 Hz and higher frequencies) to the fuel cell stack. This periodic action enables impedance measurement without requiring the lengthy scanning process of traditional EIS, significantly reducing testing time while maintaining the ability to analyze electrode reaction characteristics through frequency-specific responses.
Solution Approach 2:
The patent changes the frequency parameter of the applied current to optimize measurement efficiency. By using alternating current at specific frequencies rather than the broad frequency sweep required by traditional EIS, the system achieves rapid impedance measurement that preserves electrode reaction analysis capability while reducing testing time from hours to minutes.
3Reliability
If traditional monitoring systems are used, then voltage data can be collected, but real-time fault diagnosis and maintenance cannot be achieved
Solution Approach 1:
The patent implements a feedback mechanism where voltage measurements from multiple points are continuously compared and analyzed. The system calculates voltage differences and provides real-time feedback on cell stack health status, enabling immediate fault detection and diagnosis. This feedback loop maintains high operational reliability while achieving real-time monitoring efficiency through continuous data acquisition and analysis.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and cost-effective real-time monitoring and fault diagnosis of fuel cell stacks, improving operational reliability and reducing maintenance complexities by applying summed frequency currents to calculate THD and impedance, thereby identifying faults promptly.
Implementation Method 1
extracting a first frequency current and a second frequency current by passing alternating currents of different frequencies through a plurality of filters, respectively
Implementation Method 2
A fuel cell is a kind of power generating device that does not convert chemical energy of fuel into heat by combustion, but converts the chemical energy into electrical energy by an electrochemical reaction in a stack
Implementation Method 3
a membrane electrode assembly (MEA) in which catalyst electrode layers in which an electrochemical reaction occur are attached to both sides of a solid polymer electrolyte membrane through which hydrogen ions move
Data Source
AI summary
Disclosed herein is a method for generating an injected current of a fuel cell stack performed in an apparatus for generating an injected current of a fuel cell stack, the method including: extracting a first frequency current and a second frequency current by passing alternating currents of different frequencies through a plurality of filters, respectively; generating a summed frequency current by summing the first frequency current and the second frequency current; and applying the summed frequency current to the fuel cell stack. Therefore, it is possible to operate the fuel cell stack by applying the summed current obtained by summing the alternating current for calculating the total harmonic distortion (THD) and the alternating current for calculating the impedance to the fuel cell stack.