Rail Vehicle Drive System Diode Energy Storage Management

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Solution Overview

Problem

Existing electrical drive systems for rail vehicles with parallel electrical and electrochemical energy stores face inefficiencies due to the different charging and discharging characteristics of these energy sources, leading to suboptimal energy management and reduced service life of the electrochemical energy store from high-power short-term usage.

Innovation Solution

Incorporating a diode to prevent charge flow from the electrical energy store to the electrochemical energy store during discharge, allowing the electrical energy store to cover high-power demands initially and shifting energy use to the electrochemical store when it is fully charged, while using a separate charging device and converters to manage voltage levels and ensure optimal energy distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electrical energy store and electrochemical energy store are connected in parallel without a diode, then the circuit complexity is reduced, but the charge from the electrical energy store flows away to the electrochemical energy store which is generally less charged, causing the electrical energy store to discharge completely and reducing system efficiency

Engineering Contradiction:
Improvecircuit complexityVSAvoidenergy loss from charge flow
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

A diode is introduced as an intermediary component in the connecting line between the electrical energy store and electrochemical energy store. The diode allows current to flow in only one direction, preventing the electrical energy store from discharging into the electrochemical energy store when the latter has lower charge level, thus avoiding energy loss while maintaining circuit simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the energy management system by introducing a diode that creates directional control over energy flow between the two energy stores. This segmentation allows independent management of charging and discharging paths, enabling the electrical energy store to supply high power during braking while preventing unnecessary discharge into the electrochemical store

Inventive Principle:
Principle #1Segmentation

2Power

If the electrochemical energy store is used for short-term high-power charging and discharging, then the immediate energy demand is met, but the service life of the electrochemical energy store is significantly reduced

Engineering Contradiction:
Improvemaximum output powerVSAvoidservice life of electrochemical energy store
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The system dynamically assigns different operational roles to each energy store based on real-time conditions. The electrical energy store (capacitor) handles high-power short-duration demands like braking energy recovery, while the electrochemical energy store (battery) manages sustained lower-power operations, optimizing both power delivery and component longevity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of each energy store - the electrical energy store operates at high current and high power for short periods, while the electrochemical energy store operates at lower current and lower power for extended periods, matching each store's optimal performance characteristics

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the electrical energy store discharges completely to the electrochemical energy store, then all energy is utilized, but the electrical energy store cannot cover high-power demands and the energy management becomes inefficient

Engineering Contradiction:
Improveenergy utilization efficiencyVSAvoidmaximum output power capability
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The diode acts as a mediator that controls energy flow direction, ensuring the electrical energy store maintains sufficient charge to provide high-power output when needed. It prevents complete discharge into the electrochemical store by blocking reverse current flow when voltage levels equalize or reverse

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach optimizes energy usage by leveraging the strengths of both energy types, extending the service life of the electrochemical energy store and minimizing circuit complexity, ensuring high output during short periods and lower power over longer durations.

Implementation Method 1

the component, which is a diode according to the invention, advantageously and in a simple manner prevents the charge from the electrical energy store from flowing away to the electrochemical energy store

Methodology Applied
Scientific EffectDiode effect: Diode

Implementation Method 2

The electrical energy storage is z. B. a double-layer capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

A suitable electrochemical energy store is z. B. a commercially available battery in which a chemical reaction takes place

Methodology Applied
Scientific EffectChemical reaction: Redox Reactions

Data Source

PatentEP2193589B1Electric drive system of an electric railroad comprising an high energy and high power energy storage system
Publication Date: 2019.03.13 SIEMENS MOBILITY GMBH
  • EP2193589B1 patent drawingFigure 1~2
  • EP2193589B1 patent drawingFigure 3~4

AI summary

The invention relates to an electric drive system, in particular for a rail vehicle, comprising an electric energy accumulator (2) and an electrochemical energy accumulator (3), connected in parallel. According to the invention, a component, e.g. a diode (4) with a transmission direction facing away from the electrochemical energy accumulator, is situated in a connecting line between the electric energy accumulator (2) and the electrochemical energy accumulator (3).