Fuel Cell Rail Powertrain With DC/DC Bus Redundancy
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Solution Overview
Problem
Existing rail vehicle powertrains with fuel cells are inflexible due to voltage levels that are not suitable for all components, leading to inefficient operation and reduced operational reliability.
Innovation Solution
A rail vehicle design featuring a power supply unit with multiple fuel cells, DC/DC converters, and a DC-Bus system that allows for flexible voltage distribution and redundant power supply units, enabling operation across various components and ensuring high operational reliability even if one power supply unit fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single voltage level is used in the powertrain, then the system structure is simplified, but the voltage is not suitable for all components leading to inefficient operation
Solution Approach 1:
The patent implements multiple DC/DC converters with different voltage transformation ratios to provide different voltage levels to various components. This allows the powertrain to operate different components at their optimal voltage levels, improving operational efficiency while maintaining a relatively simple system structure through standardized converter modules.
Solution Approach 2:
The DC/DC converters are designed to serve multiple functions: they can operate in different switching modes (first switching mode for voltage step-up, second switching mode for voltage step-down) and can be configured to provide different output voltages. This multi-functionality allows a single converter design to serve multiple voltage requirements throughout the powertrain.
2Reliability
If the voltage level is dominated by the battery, then the battery can provide stable voltage, but the voltage level is not suitable for other powertrain components
Solution Approach 1:
The DC/DC converters act as intermediary devices between the battery and other powertrain components. They transform the battery's voltage level to appropriate levels for fuel cells, auxiliary systems, and other components, enabling voltage compatibility across the entire powertrain while maintaining the battery's stable voltage output.
Solution Approach 2:
The DC/DC converters dynamically adjust voltage transformation ratios to match the specific voltage requirements of different components. This allows the system to adapt voltage levels to suit various components while the battery continues to provide stable voltage, resolving the conflict between voltage stability and voltage compatibility.
3Reliability
If redundant power supply units are added, then operational reliability is improved, but the system complexity and cost increase
Solution Approach 1:
The power supply system is segmented into multiple independent power supply units, each capable of independently supporting the powertrain. This modular segmentation allows the system to maintain high operational reliability through redundancy while managing complexity through standardized, repeatable module designs that can be independently tested and replaced.
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 solution provides a flexible and reliable power distribution system that optimizes voltage levels for multiple components, enhancing the operational efficiency and reliability of the rail vehicle by allowing continued operation even if one power supply unit fails.
Implementation Method 1
A DC/DC converter is a DC voltage converter which converts an electrical DC voltage supplied at the input into an electrical DC voltage with a higher voltage level or into an electrical DC voltage with a lower DC voltage level at the output
Implementation Method 2
a first power supply unit with at least one, preferably at least two fuel cells
Data Source
AI summary
The invention concerns a rail vehicle (1) comprising a first power supply unit (5) which has at least one, preferably at least two, fuel cells (7), at least one fuel storage (8) and a first fuel cell power converter (10). The first fuel cell power converter (10) comprises a DC/DC converter (12) for each fuel cell (7), the DC/DC converters (12) preferably have outputs which are connected in parallel. The first power supply unit (5) is preferably arranged in a powerpack (2).