LV-DC Ring Bus Layout for Converter Fault Isolation

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Solution Overview

Problem

DC distribution systems face reliability issues when the source converter or energy storage system malfunctions, as they rely on a single source converter and energy storage system, leading to potential system failure.

Innovation Solution

A DC distribution system with a ring structure and normal-open ring switches, where each power consumer cluster is connected to a common LV-DC ring bus and fed by a MV-DC/DC converter, which is backed by an AC/DC converter connected to a MV-AC grid, allowing for independent energy storage and self-operated or controlled switches to disconnect faulty components and reroute power from neighboring clusters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single source converter and energy storage system are used, then the device complexity is reduced, but the reliability deteriorates because the system cannot operate reliably when these components malfunction

Engineering Contradiction:
Improvesystem reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The DC distribution system is divided into multiple independent power consumer clusters (first cluster, second cluster, etc.), each with its own source converter and energy storage system. The ring bus structure segments the system into isolated sections that can operate independently, allowing the system to maintain reliability when one segment fails while managing complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Normal-open ring switches are pre-installed at strategic locations between power consumer clusters before any malfunction occurs. These switches remain open during normal operation but can be quickly closed to reroute power when a malfunction is detected, enabling preliminary preparation for fault tolerance without adding complex control systems

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a ring bus structure with multiple power consumer clusters is implemented, then the reliability is improved through redundancy, but the device complexity increases due to additional converters, switches, and bus structure

Engineering Contradiction:
Improvepower distribution reliabilityVSAvoiddistribution system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple power consumer clusters are merged into a unified ring bus structure where each cluster shares the common DC ring bus. This merging approach provides redundancy and reliability through multiple power paths while managing complexity by using a shared infrastructure rather than completely separate systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Normal-open ring switches are installed in advance at specific locations on the ring bus to enable quick isolation and rerouting of faulty sections. These switches remain open during normal operation and are only activated when malfunctions occur, providing fault tolerance capability without adding complex control mechanisms

Inventive Principle:
Principle #10Preliminary action

3Reliability

If normal-open ring switches are used to separate power consumer clusters, then the reliability is improved by isolating faults, but the device complexity increases due to additional switching components

Engineering Contradiction:
Improvefault isolation capabilityVSAvoidswitching system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Normal-open ring switches are pre-installed at strategic locations between power consumer clusters before any malfunction occurs. These switches remain open during normal operation but can be quickly closed to reroute power when a malfunction is detected, enabling preliminary preparation for fault tolerance without adding complex control systems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The switching function is extracted as a separate, simple component (normal-open ring switch) that can be independently controlled. This extraction allows the switching mechanism to be simplified and managed separately from the power conversion and distribution functions, reducing overall system complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4274046B1DC distribution system and method for distributing power
Publication Date: 2024.11.13 ABB E-MOBILITY BV
  • EP4274046B1 patent drawingFigure 1
  • EP4274046B1 patent drawingFigure 2
  • EP4274046B1 patent drawingFigure 3

AI summary

The invention is related to a DC distribution system (100) comprising a plurality of power consumer clusters (120) each comprising at least one power consumer (180). The power consumer clusters (120) are arranged as a ring structure with a common LV-DC ring bus (102). Each power consumer (180) is connected to the LV-DC ring bus (102). The DC distribution system (100) further comprises a plurality of normal-open ring switches (110). Each power consumer cluster (120) is separated from its adjacent power consumer clusters by one of the normal-open ring switches (110). Each power consumer cluster (120) is fed by a MV-DC/DC converter (130), which in turn is fed by a MV-AC/DC converter (145) connected to a MV-AC grid (104).