Fuel Cell Stack Diagnosis via Motor Efficiency Variance
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Solution Overview
Problem
Current methods for diagnosing fuel cell stacks face challenges in accurately determining their state without causing heat issues or durability problems in external energy consumption devices, particularly when dealing with low output current variances.
Innovation Solution
A method and system using cooperative control logic between controllers to diagnose fuel cell stacks by adjusting motor efficiency values and analyzing voltage variance, eliminating the need for an external energy consumption device and ohmic value analyzer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external energy consumption device and resistance analyzer are used to measure ohmic value for diagnosing fuel cell stack, then measurement precision is improved, but device complexity and durability problems increase due to heat generation
Solution Approach 1:
The patent extracts the diagnostic function from external dedicated devices (energy consumption device and resistance analyzer) and integrates it into the existing motor controller and fuel cell controller. The motor controller's existing capabilities are utilized to perform efficiency value adjustment and voltage measurement, eliminating the need for separate diagnostic hardware while maintaining measurement precision.
Solution Approach 2:
The patent makes existing controllers multi-functional by enabling them to perform both their primary functions (motor control, fuel cell management) and diagnostic functions (ohmic value measurement). The motor controller adjusts efficiency values and measures voltage, while the fuel cell controller analyzes the data, allowing one system to serve multiple purposes without adding dedicated diagnostic equipment.
2Measurement precision
If an external energy consumption device is used for diagnosis, then measurement precision is improved, but reliability decreases due to heat problems and durability issues
Solution Approach 1:
The system uses itself for diagnosis - the motor controller uses its own existing components (motor, voltage sensors) to perform the diagnostic measurement without requiring external energy consumption devices. The fuel cell stack's own operational characteristics are utilized to generate the necessary test conditions, eliminating the need for separate testing equipment that would generate heat and reduce reliability.
3Measurement precision
If traditional diagnosis methods are used, then measurement precision is improved, but loss of time increases due to inability to diagnose under low output current conditions
Solution Approach 1:
The patent implements dynamic efficiency value adjustment during motor operation, allowing the system to transition between different efficiency states (first efficiency value and second efficiency value) based on operating conditions. This dynamic approach enables accurate ohmic value measurement even during low output current periods by adjusting the efficiency value to optimize the measurement signal, rather than requiring separate high-current test periods.
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 continuous and accurate diagnosis of fuel cell stack states without additional hardware, solving durability issues and allowing for rapid detection of dry-out conditions.
Implementation Method 1
driving a motor adjusted to a first efficiency value for a predetermined first reference time period; driving the motor adjusted to a second efficiency value after the first reference time period has elapsed
Implementation Method 2
hydrogen ions are extracted through a catalysis reaction at the fuel electrode. The separated hydrogen ions are delivered to the anode through an electrolyte membrane, and the hydrogen ions and electrons from the fuel electrode produce an electrochemical reaction with oxygen to generate electric energy at the anode
Data Source
AI summary
A system and method for diagnosing a fuel cell stack are provided. The method includes determining, by a controller, a time at which diagnosing the fuel cell stack is required based on a plurality of factors and driving a motor adjusted to a first efficiency value for a predetermined first reference time period based on the diagnosis determination. In addition, the controller is configured to drive the motor adjusted to a second efficiency value when the first reference time period has elapsed. A state of the fuel cell stack is then diagnosed based on a voltage variance of the fuel cell stack between driving the motor adjusted to the first efficiency value and second efficiency value.