Fuel Cell Converter Failure Mode for Range Preservation
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Solution Overview
Problem
Fuel cell electric vehicles experience significantly reduced travel distance when a fuel cell converter fails, as they rely solely on a secondary battery for power, leading to short travel distances.
Innovation Solution
A fuel cell system with a control unit that detects voltage boosting-disabling failures in the fuel cell converter and switches to passing current through it, ensuring continuous electricity supply from the fuel cell, even if voltage boosting is impaired, thereby preventing travel distance reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel cell converter is shut off upon failure from the viewpoint of fail-safety, then system reliability is improved, but the travel distance is significantly reduced
Solution Approach 1:
The patent applies dynamics by enabling the fuel cell converter to dynamically switch between normal voltage boosting mode and failure mode (current passing only). Instead of a static shut-off design, the system adapts its operational state based on failure detection, allowing it to maintain partial functionality (current passage) while protecting against catastrophic failure, thus preserving travel distance while ensuring safety.
Solution Approach 2:
The patent changes the operational parameters of the fuel cell converter from a binary state (on/off) to a continuous spectrum of operation modes. By detecting voltage boosting failures and switching to current-passing mode, the system changes the electrical parameters (voltage boosting capability vs. current conduction), allowing the converter to remain in the circuit in a degraded but functional state, thereby extending travel distance while maintaining fail-safety.
2Reliability
If the fuel cell converter is shut off upon failure, then safety is ensured, but electricity supply continuity is compromised
Solution Approach 1:
The patent ensures continuity of useful action by maintaining the fuel cell converter in the electrical circuit even after failure detection. Instead of complete shut-off, the converter continues to pass current from the fuel cell to the load, albeit without voltage boosting capability. This continuous current passage preserves electricity supply continuity while the control unit manages the degraded operation safely.
Solution Approach 2:
The control unit acts as an intermediary that mediates between the failed fuel cell converter and the load. Upon detecting voltage boosting failure, the control unit switches the converter to current-passing mode, effectively mediating the degraded state and maintaining electrical continuity. This intermediary control enables the system to tolerate converter failure while preserving overall system functionality and electricity supply continuity.
3Reliability
If the fuel cell converter is designed to be shut off on failure, then fail-safety is achieved, but the vehicle operational range is limited
Solution Approach 1:
The patent makes the fuel cell converter dynamic in its failure response, transitioning from a static shut-off design to a dynamic current-passing mode. This dynamic adaptation allows the converter to remain operational in a degraded state, extending the vehicle's operational range while maintaining fail-safety through controlled degradation rather than complete system shutdown.
Solution Approach 2:
The patent changes the operational parameters of the fuel cell converter upon failure detection, switching from voltage boosting mode to current conduction mode. This parameter change allows the converter to continue functioning as a current pathway even without voltage multiplication capability, thereby extending vehicle operational range while preserving fail-safety through parameter adaptation rather than system shutdown.
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 solution allows for continuous electricity supply to the load, preventing the shortening of travel distance in fuel cell electric vehicles by utilizing the fuel cell directly when the converter fails, rather than relying solely on the secondary battery.
Implementation Method 1
a fuel cell that supplies electricity to a load
Implementation Method 2
a fuel cell converter that is connected between the fuel cell and the load and boosts a voltage output from the fuel cell
Data Source
AI summary
Provided is a fuel cell system including: a fuel cell that supplies electricity to a load; a fuel cell converter that is connected between the fuel cell and the load and boosts a voltage output from the fuel cell; and a control unit that causes the fuel cell converter to perform a voltage boosting action and controls output electricity to the load. Upon detecting a voltage boosting disabling failure that is a failure in which the fuel cell converter is unable to perform the voltage boosting action and able to pass a current, the control unit stops the voltage boosting action of the fuel cell converter and passes a current through the fuel cell converter.