Fuel Cell Stack Power Distribution Under Battery SOC Constraints
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Solution Overview
Problem
Fuel cell electric vehicles face inefficiencies due to the limitations of distributing output power between the high-voltage battery and fuel cell stack, which can lead to unsatisfied motor output power requirements and discontinuous fuel cell stack output, especially considering state of charge (SOC) and discharge limits.
Innovation Solution
A method and system that dynamically adjust the output power distribution ratio between the fuel cell stack and battery based on the SOC of the battery, ensuring stable SOC management and continuous output power, while correcting the fuel cell stack's output power according to the battery's dischargeable amount to meet motor requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If output power is distributed based on a predetermined ratio between battery and fuel cell stack, then power distribution is simplified, but the required motor output power may not be satisfied depending on battery SOC or discharge limit
Solution Approach 1:
The patent applies dynamics by making the output power distribution ratio variable rather than fixed. The controller dynamically adjusts the distribution ratio between the battery and fuel cell stack based on real-time battery SOC and discharge limit conditions, ensuring that motor output power requirements are always met while optimizing system performance.
Solution Approach 2:
The patent changes the parameter of output power distribution ratio from a constant predetermined value to a variable parameter that adapts to battery SOC and discharge limit conditions. This allows the system to optimize power distribution under different operating conditions and ensure motor power requirements are satisfied.
2Device complexity
If output power is distributed based on a predetermined ratio, then control is simplified, but the output power of the fuel cell stack may increase discontinuously
Solution Approach 1:
The patent implements feedback control by continuously monitoring battery SOC and discharge limit conditions, then using this information to adjust the output power distribution ratio. This feedback mechanism ensures smooth, continuous adjustment of fuel cell stack output power and prevents discontinuous increases.
3Device complexity
If only the battery is responsible for charging or discharging, then system control is simplified, but durability of the battery deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the power management responsibilities between the battery and fuel cell stack based on SOC and discharge limit conditions. The battery handles power demands within its safe operating range, while the fuel cell stack supplements power when needed, reducing battery stress and extending durability.
Solution Approach 2:
The patent makes the power supply system multi-functional by enabling both the battery and fuel cell stack to contribute to power delivery based on real-time conditions. This universal approach allows either component to fulfill power requirements depending on SOC and discharge limits, reducing battery degradation.
Data Source
AI summary
An embodiment method of controlling a fuel cell electric vehicle includes determining a required output power amount of a fuel cell stack from a total required output power amount of a battery and the fuel cell stack based on an output power distribution ratio of the fuel cell stack according to a current state of charge (SOC) value of the battery and controlling an operation of the fuel cell stack based on the required output power amount of the fuel cell stack.