Three-Stage DC Power Filter Layout for Low-Loss EMI Suppression

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Solution Overview

Problem

Existing filters for direct-current power supplies in high-voltage and high-power density electric drive controllers face issues with high insertion loss, stray inductance, inflexible volume structure, and high maintenance costs, leading to electromagnetic interference and failure to meet stringent filtering requirements, especially with the use of third-generation silicon carbide power semiconductors.

Innovation Solution

A filter design comprising a base with a power charging, positive, and negative copper bar, and three stages of filter components, including magnetic rings and capacitors, integrated to provide power and filtering functions, with a compact layout and high resistance to insertion loss, using amorphous and ferrite magnetic rings to address different frequency ranges of interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional filter structures are used in high-voltage and high-power density electric drive controllers, then the filtering function is provided, but the insertion loss is high and stray inductance is generated

Engineering Contradiction:
Improvefiltering performanceVSAvoidinsertion loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The filter is divided into three stages with different filtering characteristics. Each stage targets specific frequency ranges of electromagnetic interference, allowing optimized filtering performance without excessive insertion loss across the entire frequency spectrum. The segmentation enables selective filtering where each stage addresses particular interference bands rather than attempting to filter all frequencies uniformly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different filter components are strategically positioned at specific locations within the filter housing. The first-stage filter component is disposed closer to the input terminals while the second and third-stage components are distributed at intervals along the output direction, creating localized filtering zones that optimize the filtering effect at different points in the power flow path.

Inventive Principle:
Principle #3Local quality

2Reliability

If traditional filter structures are used, then filtering is provided, but the volume structure is inflexible and layout is bulky

Engineering Contradiction:
Improvefiltering functionVSAvoidfilter volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

Multiple filter components with different filtering characteristics are integrated into a single filter housing structure. The housing combines the first-stage filter component, second-stage filter component, and third-stage filter component into one unified assembly, reducing the overall volume compared to separate filter units while maintaining comprehensive filtering capability across multiple frequency ranges.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The filter components are arranged in a three-dimensional configuration within the housing rather than a simple linear or planar layout. The second and third-stage filter components are distributed at intervals along the output direction, utilizing spatial dimensionality to optimize the filtering path length and component spacing without increasing the overall footprint of the filter assembly.

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

3Power

If conventional filter designs are used, then power supply is provided, but maintenance costs are high

Engineering Contradiction:
Improvepower supply functionVSAvoidmaintenance cost
Core Design Contradiction:
PowerVSEase of repair

Solution Approach 1:

The filter is segmented into three independent stages that can be individually accessed and maintained. Each filter component is disposed within the housing in a manner that allows separate replacement or repair of specific stages without requiring complete disassembly of the entire filter assembly, reducing maintenance complexity and cost while ensuring continuous power supply functionality.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If existing filter structures are used, then basic filtering is achieved, but electromagnetic interference problems persist due to high insertion loss and stray inductance

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidinsertion loss
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

Each filter stage is designed with specific local characteristics optimized for particular frequency ranges of electromagnetic interference. The first-stage filter component addresses lower frequency interference closer to the input, while the second and third-stage components handle higher frequency interference further along the output path, creating localized filtering zones that effectively suppress electromagnetic interference without requiring high insertion loss across all frequencies.

Inventive Principle:
Principle #3Local quality

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 design achieves high resistance to insertion loss, meets strict filtering requirements, ensures stable signal transmission, and reduces maintenance costs with a simple, compact structure, suitable for vehicles with high-voltage electric drive controllers.

Implementation Method 1

using amorphous and ferrite magnetic rings to address different frequency ranges of interference

Methodology Applied
Scientific EffectMagnetic filtering: Magnetic Field

Implementation Method 2

a power charging copper bar, assembled to the base; a power positive copper bar, assembled to the base; a power negative copper bar, assembled to the base

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4686063A1Filter of direct-current power source, and electric drive controller and vehicle
Publication Date: 2026.01.28 ZHEJIANG ZEEKR INTELLIGENT TECH CO LTD
  • EP4686063A1 patent drawingFigure 1
  • EP4686063A1 patent drawingFigure 2~3
  • EP4686063A1 patent drawingFigure 4~5

AI summary

Disclosed in the present application are a filter of a direct-current power source, and an electric drive controller and a vehicle. The filter of a direct-current power source comprises a base, a power source charging copper bar, a power source positive copper bar, a power source negative copper bar and at least three stages of filtering assemblies, wherein the power source charging copper bar, the power source positive copper bar, the power source negative copper bar and the at least three stages of filtering assemblies are all assembled on the base, and the at least three stages of filtering assemblies are electrically connected to the power source charging copper bar, the power source positive copper bar and the power source negative copper bar, respectively.