Capacitive Feedthrough Filter Assembly for Compact EMI Attenuation

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Solution Overview

Problem

Existing electromagnetic filter assemblies face a trade-off between production costs, compactness, and filter performance, with high-performance filters being costly and bulky.

Innovation Solution

An electromagnetic filter assembly featuring a base plate with electrically isolated conductive layer sections and discrete capacitor elements, allowing for effective interference attenuation while maintaining compactness and cost-efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-performance electromagnetic filter assemblies are used to achieve good filter performance, then filter performance is improved, but production costs increase and compactness deteriorates

Engineering Contradiction:
Improvefilter performanceVSAvoidproduction costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The base plate is segmented into multiple electrically isolated conductive layer sections (first layer section, second layer section) that are capacitively coupled through discrete capacitor elements. This segmentation allows the filter assembly to achieve high filter performance through multiple capacitively coupled sections while using simple, inexpensive discrete components instead of complex integrated structures, thereby reducing production costs while maintaining compactness.

Inventive Principle:
Principle #1Segmentation

2Reliability

If high-performance electromagnetic filter assemblies are used to achieve good filter performance, then filter performance is improved, but the device size increases (low compactness)

Engineering Contradiction:
Improvefilter performanceVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The discrete capacitor elements are mounted directly on the base plate between the conductive layer sections, nesting the filtering components within the existing structural footprint. This integration allows multiple filtering stages (multiple capacitively coupled layer sections) to be accommodated within a compact area, achieving high filter performance without proportionally increasing device size.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The filter assembly utilizes the vertical dimension by stacking multiple conductive layer sections at different heights on the base plate, with capacitor elements providing capacitive coupling between layers. This three-dimensional arrangement of capacitively coupled sections achieves high filter performance while maintaining a compact planar footprint, as the filtering action occurs across multiple vertical layers rather than requiring extended horizontal space.

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

3Reliability

If multiple capacitively coupled layer sections are implemented, then filter performance is improved, but device complexity increases

Engineering Contradiction:
Improvefilter performanceVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The base plate itself serves multiple functions: it provides mechanical support for the conductive layer sections and capacitor elements, establishes electrical isolation between layer sections through its non-conductive structure, and provides mounting surfaces for the discrete capacitor elements. This self-service approach of the base plate reduces overall device complexity by consolidating support, isolation, and mounting functions into a single component rather than requiring separate structures for each function.

Inventive Principle:
Principle #25Self-service

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 assembly achieves efficient electromagnetic interference attenuation with reduced size and production costs, suitable for conductors carrying high currents and voltages, and is applicable in vehicles.

Implementation Method 1

The first layer section and the second layer section are capacitively coupled via at least two discrete capacitor elements

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The first layer section comprises a shielding interface configured to connect the first layer section to a shielding in an electrically conductive manner

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP4344371B1Electromagnetic filter assembly for attenuating electromagnetic interferences, feedtrhough assembly, enclosure assembly and vehicle
Publication Date: 2025.08.20 VOLVO CAR CORP
  • EP4344371B1 patent drawingFigure 1~2
  • EP4344371B1 patent drawingFigure 3~4
  • EP4344371B1 patent drawingFigure 5~6

AI summary

The disclosure relates to an electromagnetic filter assembly (44) for attenuating electromagnetic interferences. The filter assembly (44) comprises a base plate (46) having a first opening (48) being configured to be penetrated by a first conductor (52) from which the electromagnetic interference at least partially originates. The base plate (46) has an electrically non-conductive carrier layer (56), an electrically conductive first layer section and an electrically conductive second layer section. The first layer section comprises a shielding interface (64) configured to connect the first layer section to a shielding (66). The second layer section comprises a first conductor interface (74). The first layer section and the second layer section are capacitively coupled via at least two discrete capacitor elements (C2, C3). Moreover, a feedthrough assembly (42) is presented which comprises such an electromagnetic filter assembly (44). Additionally, an enclosure assembly (28) having an electromagnetic filter assembly (44) and a vehicle comprising an enclosure assembly (28) are explained.