Dual-Voltage Traction Drive Layout for Rail Vehicle Battery Power

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Solution Overview

Problem

Existing drive systems for rail vehicles face challenges in efficiently adapting battery voltage levels from low voltage to medium voltage required for high power applications, leading to inefficiencies and increased component costs.

Innovation Solution

A drive system comprising two subsystems with different voltage levels, where the first subsystem has a battery controller to step up the voltage level of the DC intermediate circuit, and the second subsystem operates at the same voltage level as its energy storage device, allowing for efficient power distribution and reduced component requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a battery controller (DC/DC converter) is used to step up voltage from low voltage to medium voltage, then the voltage level is adapted for high power applications, but device complexity and component costs increase

Engineering Contradiction:
Improvepower outputVSAvoidsystem complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The drive system is divided into two independent subsystems: a first subsystem with a battery controller for medium voltage/high power applications, and a second subsystem operating at low voltage without a battery controller. This segmentation allows each subsystem to be optimized independently, reducing overall system complexity while maintaining high power capability where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The battery controller and voltage step-up functionality are applied locally only to the first subsystem where high power is required, rather than uniformly across the entire drive system. The second subsystem operates without these components, reducing overall device complexity and cost while maintaining adequate performance for lower power demands.

Inventive Principle:
Principle #3Local quality

2Power

If a battery controller is used to adapt voltage levels, then medium voltage can be achieved for high power, but component costs and weight increase

Engineering Contradiction:
Improvepower outputVSAvoidcomponent weight
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The drive system is divided into two independent subsystems: a first subsystem with a battery controller for medium voltage/high power applications, and a second subsystem operating at low voltage without a battery controller. This segmentation allows each subsystem to be optimized independently, reducing overall system complexity while maintaining high power capability where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The battery controller and voltage step-up functionality are applied locally only to the first subsystem where high power is required, rather than uniformly across the entire drive system. The second subsystem operates without these components, reducing overall device complexity and cost while maintaining adequate performance for lower power demands.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If two subsystems with different voltage levels are used, then power distribution is optimized and component costs are reduced, but device complexity increases

Engineering Contradiction:
Improvecomponent costVSAvoidsystem complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

Both the first and second subsystems can supply motors, providing universal power distribution capability. The system can operate with one or both subsystems active, and motors can be supplied by either subsystem depending on power requirements, enhancing flexibility while maintaining manageable complexity through standardized interfaces.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables a more powerful and cost-effective drive system by optimizing voltage levels, reducing component costs and weight, and allowing for flexible power distribution between the two subsystems.

Implementation Method 1

the first DC intermediate circuit is connected to the first energy storage device via a battery controller such that the voltage level of the first DC intermediate circuit is higher than that of the first energy storage device

Methodology Applied
Scientific EffectVoltage transformation:

Data Source

PatentEP4063169B1Vehicle traction system
Publication Date: 2025.06.18 SIEMENS MOBILITY GMBH
  • EP4063169B1 patent drawingFigure 1
  • EP4063169B1 patent drawingFigure 2
  • EP4063169B1 patent drawingFigure 3

AI summary

The invention relates to a drive system for a vehicle, comprising a first subsystem (MV-SYS) with a first electrical energy storage device (BAT1) and a first DC link (DC-ZK), and a second subsystem (LV-SYS) with a second electrical energy storage device (BAT2) and a second DC link (DC-ZK). Each DC link (DC-ZK) supplies at least one motor (M1, M2, M3, M4). The first DC link (DC-ZK) is connected to the first energy storage device (BAT1) via a battery controller (BAT-STELL) such that the voltage level of the first DC link (DC-ZK) is higher than that of the first energy storage device (BAT1), and the voltage level of the second DC link (DC-ZK) is equal to that of the second energy storage device (BAT2).