Energy Storage Arrangement With Decoupled Backup Capacitance

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Solution Overview

Problem

Existing energy storage arrangements for multi-system vehicles, such as those operating on both 25 kV AC and 750 V DC networks, face challenges in flexible voltage adjustment and hardware complexity, particularly when dealing with significant voltage variations in the 750 V DC network.

Innovation Solution

The energy storage arrangement includes a controller with a backup capacitance and controllable controller paths, where the intermediate circuit is connected to a second controller phase, allowing the voltage at the backup capacitance to be decoupled from the intermediate circuit voltage, enabling flexible voltage adjustment and operation across variable voltage networks with minimal hardware complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the energy storage device is directly connected to the intermediate circuit, then the connection is simple, but the voltage fluctuations in the 750 V DC network make reliable operation impossible

Engineering Contradiction:
Improveconnection complexityVSAvoidreliable connection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The controller acts as an intermediary device between the energy storage device and the intermediate circuit. It includes a buffer capacitor and controllable switching paths that decouple the energy storage device from direct connection to the fluctuating intermediate circuit, thereby ensuring reliable operation while maintaining manageable complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The controller creates a buffered copy of the intermediate circuit voltage through the buffer capacitor, allowing the energy storage device to operate at a stable voltage level while the controller handles the voltage fluctuations from the intermediate circuit

Inventive Principle:
Principle #26Copying

2Reliability

If a voltage regulator is used to adjust the vehicle's DC voltage, then reliable operation on 750 V DC network is achieved, but the hardware complexity increases

Engineering Contradiction:
Improvereliable operationVSAvoidhardware complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The controller is designed to perform multiple functions: it regulates voltage for reliable operation on 750 V DC networks, manages energy storage charging/discharging, and provides buffering against voltage fluctuations. This multi-functionality reduces the need for separate dedicated voltage regulator hardware

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

Solution Approach 2:

The voltage regulation function is merged into the controller that already manages the energy storage device. The buffer capacitor and switching paths are combined in a single integrated controller unit, reducing overall hardware complexity compared to separate voltage regulator and energy storage management systems

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If the voltage at the energy storage device is raised above mains voltage for energy capacity reasons, then energy capacity improves, but compatibility with both 25 kV AC and 750 V DC networks is lost

Engineering Contradiction:
Improveenergy capacityVSAvoidnetwork compatibility
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The controller dynamically adjusts the voltage relationship between the energy storage device and the intermediate circuit through controllable switching paths. This allows the system to adapt to different network voltages (both 25 kV AC and 750 V DC) while maintaining high energy storage voltage for optimal energy capacity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes the electrical parameters (voltage, current) through its switching paths to enable the energy storage device to operate at high voltage for energy capacity while maintaining compatibility with different network voltages. The buffer capacitor voltage can be independently controlled to match different network conditions

Inventive Principle:
Principle #35Parameter changes

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 allows for flexible voltage regulation at the energy store, enabling high voltage charging with low current load, and reduces hardware complexity by using existing components like rectifier units and transformers, effectively managing voltage variations in different energy supply networks.

Implementation Method 1

Each controller path comprises a series connection of two pairs, each consisting of a switch ST and a diode D... The controller paths enable controlled energy transfer between the intermediate circuit and energy storage device

Methodology Applied
Scientific EffectElectrical energy transformation: Electromagnetic Induction

Implementation Method 2

The actuator (3) has a buffer capacitor (5) on an input side of the actuator (3)... the voltage across the controller's buffer capacitor can be raised to a level higher than the voltage across the intermediate circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3668745B1Energy storage arrangement and method for operating such energy storage arrangement
Publication Date: 2023.03.22 SIEMENS MOBILITY GMBH
  • EP3668745B1 patent drawingFigure 1
  • EP3668745B1 patent drawingFigure 2
  • EP3668745B1 patent drawingFigure 3~4

AI summary

The invention relates to an energy accumulator arrangement (1) comprising an energy accumulator (2), a regulator (3) and an intermediate circuit (4) of an energy supply (13, 14). The energy accumulator (2) can be connected to the intermediate circuit (4) by means of the regulator (3). The regulator (3) has a back-up capacitor (5) and one or more controllable regulator path(s) (6, 7, 8) which is/are connected in parallel with the back-up capacitor (5). A tap from a regulator phase (9, 10, 22) is positioned in each case on each regulator path (6, 7, 8). The energy accumulator (2) is connected to at least one first regulator phase (10) and the intermediate circuit (4) is connected to a second regulator phase (22), which is different from the first regulator phase.