Bipartite Converter Cell Segmentation for Tool-Free Handling

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Solution Overview

Problem

The assembly and disassembly of modular multilevel converter cells are cumbersome due to their weight and require tools, making it difficult to handle and replace faulty cells, especially in hard-to-reach locations.

Innovation Solution

Designing the converter cell into two separate units: a semiconductor unit and a capacitor unit, which can be easily handled and connected without tools, allowing for individual testing and adaptation, with a compact and efficient cooling system and busbar connections for electrical and mechanical linkage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the converter cell is designed as a single integrated unit, then the electrical connections are compact, but the weight makes assembly and disassembly cumbersome and requires tools

Engineering Contradiction:
Improveassembly and disassemblyVSAvoidconverter cell weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The converter cell is divided into two separate units: a semiconductor unit and a capacitor unit. Each unit has its own housing and can be handled independently. This segmentation reduces the weight of each individual unit, making them easier to assemble and disassemble without requiring tools, while maintaining the electrical connection functionality through busbar systems with terminals.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the converter cell is divided into two separate units, then the handling and replacement become easier, but the electrical connection complexity increases

Engineering Contradiction:
Improvehandling and replacementVSAvoidelectrical connection structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The busbar systems in both the semiconductor unit and capacitor unit are designed with universal terminals that serve multiple functions: electrical connection, mechanical linkage, and structural support. This multi-functionality simplifies the overall connection structure despite the division into two units, as the same busbar components perform multiple roles rather than requiring separate specialized components for each function.

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

3Manufacturing precision

If more converter cells are used in series, then the output voltage quality improves, but the overall system weight and complexity increase

Engineering Contradiction:
Improveoutput voltage qualityVSAvoidsystem structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

By dividing each converter cell into standardized semiconductor and capacitor units with uniform interfaces, the system enables easy series connection of multiple cells to improve output voltage quality. The segmentation creates modular building blocks that can be stacked in series without proportionally increasing overall system complexity, as each module follows the same design pattern with consistent connection protocols.

Inventive Principle:
Principle #1Segmentation

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

Simplifies the assembly and disassembly process, reduces the need for tools, and allows for easy adaptation of each unit to different performance levels, while minimizing weight and production costs, enabling easier handling and replacement of converter cells.

Implementation Method 1

the semiconductors of a power converter cell that can be switched off on the feed and load side generate losses, they are thermally coupled at least to a heat sink

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

Either an air heat sink or a liquid heat sink is used as the heat sink

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2681835B1Bipartite converter cell
Publication Date: 2020.07.29 SIEMENS AG
  • EP2681835B1 patent drawingFigure 1
  • EP2681835B1 patent drawingFigure 2~3
  • EP2681835B1 patent drawingFigure 4~5

AI summary

The invention relates to a bipartite converter cell (2) of a modular multilevel converter. According to the invention, in the housing (14) of a semiconductor assembly (10), at least two turn-off semiconductors (T11,T12,T21,T22) and at least two freewheeling diodes (D11,D12,D21,D22) are thermally conductively linked to a heat sink (16), wherein said turn-off semiconductors (T11,T12,T21,T22) and said freewheeling diodes (D11,D12,D21,D22) are electrically conductively connected by means of a busbar system (20), the connections (22,24,26) of which project sideways from the housing (14), wherein, in the housing (36) of a capacitor assembly (12), a multiplicity of electrolytic capacitors (34) are electrically connected in parallel and/or in series by means of a busbar system (40), wherein connections (22',24',26') of said busbar system (40) and the connections (22 ',24 ',26' ) of the semiconductor assembly (10) are electrically conductively connected in each case. A converter cell (2) of a modular multilevel converter which can be incorporated into and removed from a supporting framework of the multilevel converter without any aids is thus obtained.