Fuel Cell Current Sensor Diagnosis via Duty Map Feedback
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Solution Overview
Problem
Current sensors in fuel cell systems often fail undiagnosed within normal output ranges, leading to malfunctions and system shutdowns, as existing diagnosis methods cannot detect scaling, offset, or stuck failures effectively.
Innovation Solution
A method that calculates an estimated duty value of the hydrogen pressure control valve based on the current sensor's sensing value and compares it with the actual duty value, using a duty map to identify errors and determine sensor failures, allowing for diagnosis of disconnection, short-circuit, and performance failures, as well as scaling, offset, and stuck failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current sensor diagnosis methods are used, then simple disconnection and short-circuit failures can be detected, but scaling, offset, and stuck failures within normal output ranges cannot be detected
Solution Approach 1:
The patent applies feedback by comparing the actual duty value of the hydrogen pressure control valve with the estimated duty value calculated from the current sensor output. This feedback mechanism enables detection of sensor failures including scaling, offset, and stuck failures that conventional methods miss, while allowing the system to continue operating in emergency mode rather than shutting down immediately.
Solution Approach 2:
The patent uses the hydrogen pressure control valve duty value as an intermediary parameter to indirectly diagnose current sensor failures. By comparing actual and estimated duty values, the system can detect sensor failures within normal output ranges without requiring direct sensor testing, thus improving detection capability while maintaining system operation.
2Reliability
If the system shuts down immediately upon detecting current sensor failure, then system safety is improved, but operational continuity and productivity are reduced
Solution Approach 1:
The patent applies partial action by implementing emergency operation mode instead of complete system shutdown when sensor failures are detected. The system continues to operate with limited functionality, allowing productivity maintenance while still addressing safety concerns through degraded operation rather than total cessation.
Solution Approach 2:
The patent prepares for potential sensor failures by establishing emergency operation procedures in advance. When failures are detected through the duty value comparison method, the system transitions to pre-planned emergency mode, cushioning the impact on productivity while maintaining safety through controlled degraded operation.
3Measurement precision
If the hydrogen pressure control valve duty value comparison method is used, then diagnosis accuracy for all failure types is improved, but calculation complexity and processing time increase
Solution Approach 1:
The patent applies self-service by using the system's own operational parameters (hydrogen pressure control valve duty value and current sensor output) to diagnose sensor failures. The diagnosis process leverages existing control loop data without requiring external testing equipment or complex additional sensors, improving accuracy while limiting complexity growth to software processing only.
Data Source
AI summary
A method for diagnosing a current sensor of a fuel cell system includes calculating an estimated duty value of a hydrogen pressure control valve, corresponding to a sensing value of the current sensor, while operating the fuel cell system. The estimated duty value is compared with an actual duty value where the hydrogen pressure control valve is controlled during the operation of the fuel cell system, thereby calculating an error value between the estimated duty value and the actual duty value. The error value is compared with a critical value in a normal range, thereby determining whether a failure occurs in the current sensor. The hydrogen pressure control valve controls a pressure of hydrogen supplied to a fuel cell stack of the fuel cell system.