Fuel Cell Electrical Assembly With Bidirectional Galvanic Isolation
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Solution Overview
Problem
Fuel cell systems often suffer from undesirable leakage currents and electrical disturbances due to a lack of galvanic isolation between the fuel cell stack and the DC bus system, which can lead to failure of sensitive battery management systems and other components.
Innovation Solution
An electrical arrangement with a bidirectional galvanic isolation device is introduced to isolate the fuel cell system from the application, comprising a DC/DC converter, bidirectional galvanic isolation device, and an interruption unit to manage energy and data transfer while preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic isolation is implemented between fuel cell stack and DC bus system, then electrical disturbances and leakage currents are reduced, but device complexity increases
Solution Approach 1:
A bidirectional galvanic isolation device is introduced as an intermediary component between the fuel cell stack and the DC bus system. This isolation device includes a first DC/DC converter connected to the fuel cell stack and a second DC/DC converter connected to the DC bus system, with a transformer providing galvanic isolation between them. The intermediary structure enables electrical disturbance reduction while maintaining controlled energy transfer.
Solution Approach 2:
The electrical arrangement is segmented into distinct isolated sections: the fuel cell stack side, the galvanic isolation device with transformer, and the DC bus system side. This segmentation allows independent optimization of each section and enables the use of simpler components in each segment while achieving overall system reliability through the isolated architecture.
2Object-affected harmful factors
If bidirectional galvanic isolation device is added to prevent disturbances, then application components are protected, but manufacturing cost increases
Solution Approach 1:
The bidirectional galvanic isolation device performs multiple functions simultaneously: it provides galvanic isolation to block electrical disturbances, enables bidirectional energy transfer for regenerative braking, offers voltage conversion through DC/DC converters, and provides electrical connection between fuel cell and application. This multi-functionality reduces the need for separate protective devices, thereby controlling manufacturing costs.
Solution Approach 2:
The patent combines the galvanic isolation function with energy transfer and voltage conversion functions into a single integrated bidirectional isolation device. By merging these functions, the design eliminates the need for separate protective components and simplifies the overall electrical architecture, leading to cost-effective manufacturing despite the advanced functionality.
3Loss of energy
If galvanic isolation is implemented, then energy transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The DC/DC converters in the bidirectional galvanic isolation device are configured to dynamically adjust their operating parameters based on system conditions. This dynamic control enables optimal energy transfer efficiency across varying load conditions while managing the complexity through adaptive rather than static design approaches.
Solution Approach 2:
The isolation device utilizes parameter changes in the transformer and DC/DC converters to optimize energy transfer. By adjusting operational parameters such as switching frequencies, duty cycles, and voltage levels, the system achieves improved energy efficiency while the parameter-based control provides a manageable approach to handling device complexity.
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 significantly reduces disturbances and loads on application components, enabling efficient energy transfer in both directions and ensuring stable insulation resistance, leading to cost savings and improved system reliability.
Implementation Method 1
configured for electrically isolating the electrical power train from the application
Implementation Method 2
configured to perform a voltage conversion from an input voltage to an output voltage
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to an electrical arrangement for a fuel cell system (7) comprising: an electrical power train (10) configured for electrically connecting a fuel cell (5) to an application (1), a DC-DC converter (4) configured for converting an input voltage to an output voltage, wherein the DC-DC converter (4) has a first terminal (41) configured to be connected to the fuel cell (5), a bidirectional galvanic isolation device (3) configured for electrically isolating the electrical power train (10), wherein the bidirectional galvanic isolation device (3) has a second terminal (30) configured to be electrically connected to the application (1), a connecting line (8) which electrically connects the DC-DC converter (4) to the isolation device (3), and a branch point (9).from which a branch line (90) branches off at the connecting line (8), wherein the branch line (90) is configured to be connected to an auxiliary component system (6) of the fuel cell system (7).