Inverter Header Sub-Assembly With Enclosed Choke for EMC Robustness

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Solution Overview

Problem

Current designs for the header of a traction inverter in electric vehicles suffer from low electromagnetic compatibility (EMC) performance, failing EMC/EMI tests and having unreliable couplings prone to cracking.

Innovation Solution

The proposed solution involves an inverter assembly with a housing, a header, a bracket, a ferrite choke, and a spacer. The ferrite choke is positioned within the bracket and against the inner surface of the bracket facing the opening, fully enclosed in a circumferential direction. The spacer is disposed between the header and the choke, and the bracket is coupled to the inner surface of the housing at multiple locations, providing a secure and shielded connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a header is used in current traction inverter designs, then the inverter can be assembled, but the EMC performance is low and the coupling is unreliable

Engineering Contradiction:
ImproveEMC performanceVSAvoidheader structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the header, bracket, and choke into an integrated header sub-assembly where the bracket is formed as an integral part of the header structure, and the choke is positioned within the bracket. This merging of components improves EMC performance by creating a more robust and reliable assembly while reducing the number of separate parts that need to be coupled together.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bracket acts as an intermediary component between the header and the housing, providing a secure mounting structure that improves reliability. The bracket mediates the connection between the header and housing, distributing mechanical stresses and improving the overall structural integrity of the assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the header coupling is simplified, then assembly is easier, but the coupling becomes unreliable and prone to cracking

Engineering Contradiction:
Improvecoupling reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bracket is formed as an integral part of the header structure through merging, creating a more reliable coupling that distributes mechanical loads and reduces stress concentration points. This integrated structure eliminates the need for separate coupling components that may fail, while the overall assembly process remains manageable through the unified design.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If EMC shielding is added to the header, then EMC performance improves, but the device complexity increases

Engineering Contradiction:
ImproveEMC performanceVSAvoidheader structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The choke is integrated into the header sub-assembly by positioning it within the bracket structure, combining EMI filtering functionality with the mechanical support structure. This merging approach improves EMC performance by incorporating the choke into the existing design rather than adding it as a separate external component, thereby reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration significantly improves EMC performance by reducing electromagnetic interference (EMI) and enhancing the robustness of the header connection, thereby passing EMC/EMI tests and increasing the durability of the inverter assembly.

Implementation Method 1

a choke, wherein the choke is positioned within the bracket and against an inner surface of the bracket facing the opening, and wherein the choke is fully enclosed in a circumferential direction

Methodology Applied
Scientific EffectElectromagnetic energy absorption: Absorption (EM radiation)

Data Source

PatentEP4525572A1Systems for integrating choke into inverter header sub-assembly for improving EMC performance
Publication Date: 2025.03.19 BORGWARNER US TECHNOLOGIES LLC
  • EP4525572A1 patent drawingFigure 1
  • EP4525572A1 patent drawingFigure 2
  • EP4525572A1 patent drawingFigure 3

AI summary

An inverter assembly may include a housing with a base and side walls, wherein one of the side walls includes an opening extending through the wall, and wherein the side walls form a periphery around an interior of the housing. An inverter assembly may include a header with a body, the body having a first end and a second end, wherein the body further includes a flange disposed between the first end and the second end, and wherein a portion of the body extends through the opening such that the flange abuts the side wall. An inverter assembly may include a bracket positioned within the interior of the housing and coupled to the housing. An inverter assembly may include a choke that is fully enclosed in a circumferential direction, wherein the choke is positioned within the bracket and against an inner surface of the bracket facing the opening.