Fuel Cell Power Net High Voltage Safety Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fuel cell vehicles face risks of exposure to high voltage due to residual voltage in the main bus, especially during dangerous events like collisions, as they fail to effectively manage voltage across the entire power network, including the fuel cell stack and high-voltage battery systems.
Innovation Solution
A power net system for fuel cell vehicles incorporating a controller that operates switching units to divert power from the main bus to a load device, utilizing a reverse current blocking unit and high-voltage battery management to safely consume and reduce voltage levels, thereby preventing exposure to high voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel cell load device is used to decrease the voltage of the fuel cell stack during dangerous situations, then the voltage of the fuel cell stack is reduced, but the high voltage remains in the main bus and high-voltage loads, creating continued exposure risk
Solution Approach 1:
The patent extracts the harmful high voltage from the main bus by connecting the load device between the main bus and ground through switching units. This separates the voltage removal function from the fuel cell stack control, allowing independent management of stack voltage and bus voltage to completely eliminate high voltage exposure risks.
Solution Approach 2:
The load device serves as an intermediary element that absorbs and dissipates the high voltage energy from the main bus. By introducing this intermediate component with controlled electrical connection via switching units, the system safely transfers and removes the harmful voltage without directly affecting the fuel cell stack operation.
2Ease of operation
If the conventional fuel cell vehicle simply decreases the voltage of the fuel cell stack, then the stack voltage is reduced, but the main bus and other high-voltage loads retain high voltage, increasing exposure risk
Solution Approach 1:
The patent segments the voltage control function into two independent parts: fuel cell stack voltage control and main bus voltage control. The switching units enable separate management of these two voltage sources, allowing the stack voltage to be controlled for operation while the bus voltage is independently removed through the load device, achieving both operational simplicity and safety.
3Reliability
If the fuel cell vehicle requires a separate post process for decreasing the voltage of the fuel cell stack by removing remaining air, then the fuel cell stack voltage is reduced, but this adds system complexity compared to internal-combustion engines
Solution Approach 1:
The load device serves multiple functions: it decreases the voltage of the fuel cell stack by providing an electrical load, removes remaining air/oxygen from the fuel cell stack, and dissipates high voltage from the main bus. This multi-functional component eliminates the need for separate systems for each function, reducing overall system complexity while maintaining reliability.
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
The system efficiently removes high voltage from the main bus, reducing the risk of exposure and allowing for extended regenerative braking application, ensuring safer driving conditions by managing voltage across the fuel cell and high-voltage battery systems.
Implementation Method 1
a fuel cell stack configured to generate electrical energy from an electrochemical reaction of reaction gas
Implementation Method 2
a fuel cell load device for decreasing and removing the voltage of the fuel cell stack is connected to the fuel cell stack to remove oxygen inside the fuel cell stack
Data Source
AI summary
A power net system of a fuel cell vehicle is provided. The power net system includes a fuel cell and a first switching unit that is configured to form and block an electrical connection between an output terminal of the fuel cell and a main bus. A load device diverges and is connected between the output terminal and the first switching unit. A reverse current blocking unit is disposed between the output terminal of the fuel cell and a node from which the load device diverges and is configured to block a current flow to the output terminal of the fuel cell. A second switching unit is configured to form and block an electrical connection between the output terminal of the fuel cell and the load device. A controller operates the first and second switching units to form the electrical connection between the main bus and the load device.