Fuel Cell Stack Diagnostic Apparatus Rectangular Wave Harmonic Analysis
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Solution Overview
Problem
Current fuel cell stack diagnostic apparatuses are complex and expensive due to their reliance on DC-DC converters and inverters to apply sine waves for state diagnosis, which complicates the detection and diagnosis process.
Innovation Solution
A diagnostic apparatus that applies a rectangular wave of single frequency with a duty ratio of about 0.5 to the fuel cell stack, measuring and converting the voltage to detect even multiple harmonic components, thereby diagnosing the state without the need for a DC-DC converter or inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sine wave of multi frequency is applied to the fuel cell stack for diagnosis, then the state diagnosis can be performed, but the device complexity and cost increase due to requiring DC-DC converter and inverter
Solution Approach 1:
The patent extracts and removes the DC-DC converter and inverter from the diagnostic apparatus, replacing them with a simple rectangular wave signal generator. This extraction eliminates the complex power conversion components while maintaining the diagnostic functionality through direct rectangular wave application to the fuel cell stack.
Solution Approach 2:
The patent changes the signal type from sine wave (multi-frequency) to rectangular wave (single frequency with duty ratio 0.5). This parameter change in the input signal simplifies the required hardware while the harmonic analysis of the output voltage maintains the diagnostic capability, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If DC-DC converter and inverter are used to generate AC voltage for diagnosis, then the fuel cell stack state can be diagnosed, but the manufacturing cost increases
Solution Approach 1:
The patent removes the expensive DC-DC converter and inverter components from the diagnostic system, replacing them with a simple rectangular wave generator. This extraction significantly reduces manufacturing costs while maintaining diagnostic accuracy through the analysis of even multiple harmonic components in the voltage response.
Solution Approach 2:
The patent replaces expensive, complex power conversion components with a simple, low-cost rectangular wave signal generation method. This substitution uses inexpensive electronics to generate the diagnostic signal, making the system more affordable and easier to manufacture while preserving the essential diagnostic function.
3Measurement precision
If sine wave of multi frequency is applied for diagnosis, then the state detection can be performed, but the detection and diagnosis process becomes complicated
Solution Approach 1:
The patent changes the input signal from multi-frequency sine wave to single-frequency rectangular wave with duty ratio 0.5. This parameter change simplifies the detection process because the rectangular wave's inherent harmonic structure allows for easier identification of even multiple harmonics in the output, reducing the complexity of the analysis while maintaining diagnostic precision.
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
This approach simplifies the diagnostic process, reducing costs and complexity by effectively diagnosing the fuel cell stack state through the analysis of harmonic components, distinguishing between normal and abnormal cell states based on harmonic magnitude.
Implementation Method 1
a rectangular wave generator configured to generate a rectangular wave of a single frequency having a duty ratio of about 0.5
Implementation Method 2
measuring a voltage of the fuel cell stack and converting the voltage into a frequency such that even multiple harmonic components of the rectangular wave frequency may be detected
Implementation Method 3
detecting even multiple harmonic components of a frequency of the rectangular wave by performing frequency conversion on the measured voltage
Data Source
AI summary
An apparatus for diagnosing a state of a fuel cell stack is provided. The apparatus may diagnose the state of the fuel cell stack without including the DC-DC converter which boosts the DC voltage and the inverter which converts the boosted DC voltage into the AC voltage. In particular, the apparatus may diagnose the state of the fuel cell by applying the rectangular wave of the single frequency having a duty ration of about 0.5 to the fuel cell stack, measuring the voltage of the fuel cell stack, detecting the even multiple harmonic component of the frequency of the rectangular wave by performing the frequency conversion on the measured voltage, and then diagnosing the state of the fuel cell stack based on the magnitude of the detected harmonic component.