Flat Busbar System for Low-Inductive Power Converter Connections

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Solution Overview

Problem

Existing power converter arrangements for wind and photovoltaic systems face challenges in adapting time-varying output voltages and frequencies to a constant frequency supply network, requiring efficient and compact high-current connections between converter assemblies.

Innovation Solution

A power converter arrangement featuring identical converter assemblies with heat sinks for cooling, parallel-connected half-bridge power semiconductor modules, and a capacitor device connected via a low-inductive flat busbar system with insulating intermediate layers, ensuring a compact, mechanically stable, and high-current-carrying connection between assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional power semiconductor modules and capacitor devices are connected using traditional connection devices, then the connection provides adequate electrical connectivity, but the inductance is high and the current-carrying capacity is insufficient

Engineering Contradiction:
Improvecurrent-carrying capacityVSAvoidinductance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The connection system is divided into two separate flat metal bodies (first and second shaped metal bodies) that are arranged parallel to each other with minimal spacing. This segmentation allows each metal body to carry high current independently while maintaining low inductance through the parallel arrangement, resolving the contradiction between current-carrying capacity and inductance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection transitions from traditional point or line contacts to a planar, two-dimensional flat metal body configuration. The flat shaped metal bodies extend in area rather than height, creating a low-inductance path by distributing current across a larger surface area while maintaining minimal spacing between the parallel metal bodies.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Power

If converter assemblies are connected with adequate current-carrying capacity, then high power transmission is achieved, but the connection occupies excessive space

Engineering Contradiction:
Improvepower transmission capacityVSAvoidconnection volume
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The connection system extracts the unnecessary vertical height dimension from traditional bulky connectors. By using flat metal bodies arranged parallel with minimal spacing instead of thick or vertically stacked connections, the design achieves high power transmission capacity while minimizing the volume occupied by the connection assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flat shaped metal bodies function as thin, planar conductive elements that provide adequate current-carrying capacity for high power applications without requiring significant thickness or volume. The thin film-like structure maintains electrical performance while minimizing spatial occupation.

Inventive Principle:
Principle #30Flexible shells and thin films

3Power

If converter assemblies are connected with high current-carrying capacity, then adequate power handling is achieved, but the mechanical stability is insufficient

Engineering Contradiction:
Improvecurrent-carrying capacityVSAvoidmechanical stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The electrical connection and mechanical stabilization functions are merged into a single integrated structure. The flat shaped metal bodies serve dual purposes: providing low-inductance electrical pathways for high current while simultaneously acting as mechanical stabilizers through their parallel arrangement and minimal spacing, which prevents relative movement between converter assemblies.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connection system uses composite construction combining flat metal bodies with insulating intermediate layers. This composite structure provides both electrical functionality (current conduction through metal bodies) and mechanical stability (rigid positioning through the layered construction), resolving the contradiction between power handling and mechanical stability.

Inventive Principle:
Principle #40Composite materials

4Reliability

If converter assemblies are connected using complex connection devices, then adequate electrical connectivity is achieved, but the manufacturing difficulty increases

Engineering Contradiction:
Improveelectrical connectivityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The flat shaped metal bodies serve multiple functions simultaneously: electrical conduction, mechanical stabilization, and alignment reference. This multi-functionality eliminates the need for separate components for each function, simplifying the manufacturing process while maintaining adequate electrical connectivity and mechanical stability.

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

Solution Approach 2:

The connection system uses homogeneous flat metal body structures for both positive and negative polarity connections, rather than requiring different types of connectors. This uniformity simplifies manufacturing by standardizing the production process and reducing the variety of components that must be manufactured and assembled.

Inventive Principle:
Principle #33Homogeneity

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

The solution provides a compact, low-inductive, and high-current-carrying connection between converter assemblies, enhancing the stability and efficiency of power conversion while facilitating easy manufacturing and reduced interference susceptibility.

Implementation Method 1

Each of these converter assemblies has a heat sink for air or liquid cooling

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

heat sink for air or liquid cooling

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

This busbar system is particularly low-inductive when it is designed to be flat, that is to say is made of two flat shaped metal bodies arranged closely adjacent to one another

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2302782B1Frequency converter assembly
Publication Date: 2013.04.03 SEMIKRON DANFOSS ELEKTRONIK GMBH & CO KG
  • EP2302782B1 patent drawingFigure 1~2
  • EP2302782B1 patent drawingFigure 3~4
  • EP2302782B1 patent drawingFigure 5

AI summary

The invention relates to a power converter arrangement comprising a plurality of power converter assemblies with cooling devices, power semiconductor modules, and a capacitor assembly for each power converter assembly. The power semiconductor module is arranged adjacent to the capacitor assembly. The DC load connection elements of the power semiconductor module are connected to the capacitor assembly by means of a planar busbar, wherein the planar busbar is formed from a first and second metal component with an insulating intermediate layer, and this busbar covers the capacitor assembly in at least one orientation.The busbars of two adjacent power converter assemblies can be connected to each other with low inductance by connecting the first metal components using a first connecting body and first connecting elements, and by connecting the second metal components using a second connecting body and second connecting elements. Furthermore, the first connecting body is covered by the second connecting body.