Fuel Cell Hydrogen Pressure Estimation Under Sensor Failure
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Solution Overview
Problem
Conventional fuel cell systems face challenges in accurately estimating hydrogen pressure when multiple hydrogen pressure sensors fail simultaneously, leading to excessive or insufficient hydrogen supply to the anode, which can result in system failure and reduced fuel efficiency.
Innovation Solution
A fuel cell system with an ejector and hydrogen pressure sensor in the hydrogen supply line, along with a controller that estimates hydrogen pressure for each open or closed state of the supply and discharge valves, allowing for feedback control to maintain optimal hydrogen flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydrogen pressure sensors are used to measure hydrogen pressure for feedback control, then the supply amount of hydrogen can be controlled according to driving environment, but the sensors generate offset and fail over time leading to excessive or insufficient hydrogen supply
Solution Approach 1:
The patent creates a virtual copy of the hydrogen pressure sensor functionality through software estimation algorithms. Instead of relying solely on physical sensors that fail, the system uses a model-based estimator that calculates hydrogen pressure based on measurable parameters (supply valve position, discharge valve position, current, temperature) to generate a virtual pressure reading that continues to function even when physical sensors fail.
Solution Approach 2:
The patent replaces the mechanical/physical hydrogen pressure sensing system with a computational estimation system. The controller uses algorithmic processing of electrical signals (valve positions, current measurements, temperature sensors) to substitute for the failed mechanical pressure sensor, thereby maintaining system reliability without depending on the physical sensor's continued operation.
2Reliability
If multiple hydrogen pressure sensors are installed to compensate for sensor failure, then measurement reliability improves, but device complexity and cost increase
Solution Approach 1:
The patent makes the controller perform multiple functions: it not only controls the supply and discharge valves based on pressure feedback but also simultaneously estimates hydrogen pressure using a model-based algorithm. This multi-functionality allows the system to maintain pressure measurement capability without adding dedicated hardware, as the existing controller handles both control and estimation tasks.
Solution Approach 2:
The system uses its own existing operational parameters (valve positions, current measurements, temperature data) to self-diagnose and self-correct for pressure measurement failures. The estimation algorithm leverages data already being collected for normal operation, allowing the system to monitor its own state and compensate for sensor failures without external intervention or additional sensors.
3Productivity
If feedback control is performed based on hydrogen pressure sensor measurements, then hydrogen supply is precisely controlled, but sensor offset and failure cause control errors and system failure
Solution Approach 1:
The patent implements a dual feedback mechanism: traditional feedback from physical pressure sensors continues to operate when they function, while a parallel model-based estimation feedback path is established. When physical sensors fail, the estimation feedback automatically takes over, ensuring continuous closed-loop control of hydrogen supply without interruption or loss of precision.
Solution Approach 2:
The system prepares for sensor failure in advance by pre-developing and implementing the model-based estimation algorithm during the design phase. This cushioning measure ensures that when physical sensors eventually fail due to offset or malfunction, the system already has a ready backup method for pressure estimation, preventing control errors and system failure.
Data Source
AI summary
A fuel cell system including an ejector provided in a hydrogen supply line, a hydrogen pressure sensor provided in the hydrogen supply line at a front end portion of the ejector and configured to measure a pressure of hydrogen flowing in from a hydrogen tank, a supply valve provided in the hydrogen supply line at a front end portion of the hydrogen pressure sensor and configured to control a flow rate of the hydrogen supplied from the hydrogen tank to an anode of a fuel cell stack, a discharge valve provided in a hydrogen discharge line, and a controller that estimates the pressure of the hydrogen flowing into the anode of the fuel cell stack from a rear end portion of the ejector for each open or closed state of each of the supply and discharge valves, and controls the supply and discharge valves based on a pressure estimate value of the hydrogen, and a control method thereof.