Rail Vehicle Traction Battery Supply Using a Bidirectional Charger
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Solution Overview
Problem
Conventional power supply systems for rail vehicles are inefficient and costly when used for battery operation over short distances, such as the last mile or emergency travel, due to the need for complex and heavy DC/DC converters and additional charging infrastructure.
Innovation Solution
A power supply device for rail vehicles that includes a bidirectional charger connected between the traction accumulator and the on-board electrical system, eliminating the need for a conventional DC/DC converter and allowing for efficient charging and discharging operations without additional charging paths or interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional DC/DC converter is used to connect the traction battery to the traction intermediate circuit, then the battery can be integrated into the power supply system, but the system complexity and component weight increase significantly
Solution Approach 1:
The bidirectional charger is designed to perform multiple functions: it serves as the charging device for the traction battery during normal operation, and simultaneously acts as the power conversion device connecting the battery to the traction intermediate circuit during battery operation. This multi-functionality eliminates the need for a separate DC/DC converter, reducing system complexity while maintaining battery operation capability.
2Ease of operation
If a standard auxiliary converter is used to supply power to the on-board electrical system during battery operation, then the auxiliary systems can be powered, but energy transmission losses increase due to the converter operating at low efficiency
Solution Approach 1:
The system dynamically switches between two power supply paths for the on-board electrical system: during normal operation, power is supplied via the standard auxiliary converter from the traction intermediate circuit; during battery operation, the bidirectional charger directly supplies power to the on-board electrical system, bypassing the auxiliary converter. This dynamic configuration optimization ensures the on-board electrical system is always powered through the most efficient path available, minimizing energy losses.
3Adaptability or versatility
If additional charging infrastructure and components are installed to enable battery charging, then the rail vehicle can operate independently, but the cost and system complexity increase
Solution Approach 1:
The bidirectional charger merges the functions of the charging infrastructure with the power conversion system. The same device that charges the battery during normal operation also serves as the interface for battery operation, eliminating the need for separate charging infrastructure and reducing retrofitting complexity and costs.
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 reduces energy transmission losses, eliminates unnecessary components and costs, and increases the range of the rail vehicle by providing a more efficient and resource-saving power supply system for battery operation.
Implementation Method 1
a bidirectional charger (13), which is connected between the accumulator (10) and the on-board electrical system (3AC)... converting discharging current from the accumulator into charging current, and vice versa
Data Source
AI summary
A power supply device for a rail vehicle has a traction battery, a traction intermediate circuit, an on-board network, a bidirectional charging device, which is connected between the traction battery and the on-board network, and a first switching unit between the traction battery and the traction intermediate circuit for switching between a charging operation and a discharging operation of the traction battery. There is also described a power supply provision device, a method for discharging a traction battery of a power supply device, a method for charging a traction accumulator of a power supply device, and a rail vehicle.