Fuel Cell Voltage Control for Power Saving
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Solution Overview
Problem
Fuel cell systems face increased electric power consumption when maintaining a target opening circuit voltage during suspended power generation, which hampers responsiveness to required output changes.
Innovation Solution
A fuel cell system with two fuel cells and corresponding supply devices, controlled by a device that adjusts the operation of each fuel cell and supply device to maintain voltage within a target range, suspends power generation and stops supply device operation when output is zero, and switches between power generation and holding modes based on output thresholds to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the opening circuit voltage is held within the target range by adjusting the amount of reactive gas supplied to the fuel cell during suspended power generation, then the responsiveness of the fuel cell output when resuming power generation is secured, but the electric power consumption of the supply device increases
Solution Approach 1:
The fuel cell system is divided into multiple fuel cells (first fuel cell, second fuel cell, etc.), and the supply devices are segmented to supply reactive gas to specific fuel cells. When power generation is suspended, only the first supply device supplies reactive gas to the first fuel cell to maintain its opening circuit voltage, while the second supply device stops supplying reactive gas to the second fuel cell. This segmentation allows the system to maintain responsiveness capability while reducing overall reactive gas supply and electric power consumption.
Solution Approach 2:
Instead of maintaining the opening circuit voltage of all fuel cells within the target range during suspended power generation, the system applies partial action by maintaining only the first fuel cell's voltage while allowing the second fuel cell's voltage to drift. This partial maintenance of voltage range is sufficient to ensure system responsiveness while significantly reducing the electric power consumption of the supply devices.
2Use of energy by moving object
If electric power generation by all fuel cells is suspended when required output is zero, then the electric power consumption is reduced, but the responsiveness to required output changes deteriorates
Solution Approach 1:
The first supply device continues to supply reactive gas to the first fuel cell even when power generation is suspended, maintaining the first fuel cell's opening circuit voltage within the target range in advance. This preliminary maintenance of voltage ensures that when power generation needs to resume, the first fuel cell can respond immediately without delay, thus maintaining system responsiveness while allowing other fuel cells to be in a lower power state.
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 approach reduces electric power consumption while ensuring responsiveness to output requirements, allowing for efficient resumption of power generation and extending fuel cell lifespan by optimizing power usage and reducing fuel consumption.
Implementation Method 1
a fuel cell unit 4 which is composed of a plurality of fuel cells 4a, 4b including a first fuel cell 4a and a second fuel cell 4b
Data Source
AI summary
A fuel cell system is equipped with a fuel cell unit that is composed of a plurality of fuel cells including a first fuel cell and a second fuel cell, a first supply device and a second supply device that supply reactive gas to the first fuel cell and the second fuel cell respectively, and a control device that controls running of the first fuel cell and the second fuel cell and operation of the first supply device and the second supply device. The control device suspends electric power generation by the first fuel cell and drives the first supply device to hold an opening circuit voltage of the first fuel cell within a target range, and suspends electric power generation by the second fuel cell and stops driving the second supply device when an output P required of the fuel cell unit is equal to 0.