Rail Vehicle Circuit Voltage Conversion Unit
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Solution Overview
Problem
The existing rail vehicle power electronics systems require specific design adaptations for different national mains voltages, leading to non-standardization and increased costs, particularly for 3kV DC systems, where widespread industrial components cannot be readily used.
Innovation Solution
A voltage conversion unit with a charge transfer mechanism, comprising a first subunit at the input side and a second subunit at the load side, allows for voltage adjustment, enabling partial independence from mains voltage and reducing the need for costly, construction-intensive measures by using common power electronics components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If specific equipment is designed for different national mains voltages, then the equipment can operate with the corresponding mains voltage, but standardization efforts on the consumer side are hindered and costs increase
Solution Approach 1:
The voltage conversion unit is designed to handle multiple mains voltages (e.g., 3kV DC, 1.5kV DC, 750V DC) using the same basic equipment design. The system can operate with different mains voltages without requiring different equipment designs, achieving universality and standardization while maintaining adaptability to various national voltage standards
Solution Approach 2:
The invention changes the voltage parameter through the voltage conversion unit, which can convert between different DC voltage levels. This allows the consumer side to operate at a standardized voltage (e.g., 1.5kV DC) regardless of the mains voltage (3kV DC, 750V DC, etc.), resolving the contradiction by decoupling consumer equipment design from mains voltage variations
2Reliability
If elements of power electronics are specially designed for 3kV DC operation, then they can operate with 3kV DC mains voltage, but the construction becomes intensive and costly
Solution Approach 1:
The voltage conversion unit acts as an intermediary between the 3kV DC mains supply and the consumer equipment. It converts the high-voltage 3kV DC to a lower voltage (e.g., 1.5kV DC), allowing standard, cost-effective power electronics components to be used on the consumer side while maintaining reliable operation with 3kV DC mains voltage
Solution Approach 2:
The system is segmented into two parts: the voltage conversion unit that handles the high-voltage 3kV DC input, and the consumer equipment that operates at lower, standardized voltage. This segmentation allows the complex high-voltage handling to be isolated in a dedicated unit, while the majority of equipment can use simpler, more manufacturable components
3Power
If a conventional step-down converter or chopper is used for voltage reduction, then the mains voltage can be reduced, but the construction is intensive and costly with larger and heavier components
Solution Approach 1:
The voltage conversion unit employs periodic switching action to achieve voltage conversion. By periodically switching the connection between the mains voltage and the load voltage through the charge transfer unit, the system achieves efficient voltage reduction without requiring large, heavy components typical of conventional continuous converters
Solution Approach 2:
The invention changes the operating parameters of the power electronics components, specifically using lower-blocking IGBTs with higher switching frequencies. This parameter change allows for smaller, lighter passive components (inductors, capacitors) while maintaining the required power conversion capability, thus reducing overall circuit weight
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 achieves a standardized design for rail vehicle electrical systems, allowing operation with various mains voltages without complex adjustments, reducing component dimensioning and enabling the use of low-blocking IGBTs for power electronics, resulting in a smaller, lighter, and more flexible traction system.
Implementation Method 1
a charge transfer unit (36) arranged to transfer a charge from the first sub-unit (28h) to the second sub-unit (28t)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a circuit for a vehicle (10), in particular a rail vehicle, which during operation can be supplied with electrical energy by a network supply (12), having an input side (20), which is configured to have a network voltage (VN) provided by the network supply (12), and having a consumer side (24) that is assigned to at least one vehicle consumer (25). In order to reduce disadvantages with respect to differences in providing the network voltage in a structurally simple manner, in particular to prevent the same, the circuit according to the invention comprises a voltage converting unit (26) for providing a voltage (VC) on the consumer side (24) that is adapted to the operation of the electrical vehicle consumer (25), which voltage converting unit (26) has a first sub-unit (28h) that is assigned to the input side (20) and is under a potential (Vh) during operation, and at least one second sub-unit (28t) that is assigned to the consumer side (24) and is under a potential (Vt) during operation, and a charge-transfer unit (36), which is provided to transfer a charge from the first sub-unit (28h) to the second sub-unit (28t).