Dual-Stage Power Conversion Filtering for Vehicle EMC Noise

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Solution Overview

Problem

Existing power conversion systems in vehicles face challenges in effectively filtering low-frequency noise and reducing resonance effects between filter structures, which affect electromagnetic compatibility (EMC) performance while increasing costs and volume.

Innovation Solution

A dual-stage filter circuit system is implemented, comprising a first-stage filter circuit for filtering noise signals in a first frequency interval and a second-stage filter circuit for filtering noise signals in a second, higher frequency interval, with each stage utilizing anti-electromagnetic interference filters and capacitors/inductors to target specific frequency ranges, thereby reducing the number and parameter values of filter devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If independently arranged filter structures are used on both DC links, then each filter can address its specific frequency range, but low-frequency noise filtering performance deteriorates and resonance effects occur at high frequencies

Engineering Contradiction:
Improvenoise filtering performanceVSAvoidEMC performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent merges the filtering functions for different frequency ranges into a single integrated filter structure. The first filter circuit and second filter circuit are combined in one configuration, with the first filter handling lower frequency noise and the second filter handling higher frequency noise, eliminating the resonance problems that occur with separate independent filter structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the filtering function into two distinct filter circuits within a unified structure. The first filter circuit targets low-frequency noise generated by the inverter module, while the second filter circuit targets high-frequency noise generated by the power conversion module, allowing each to operate optimally without interfering with the other.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If additional filter circuits are added to filter low-frequency noise, then noise filtering capability improves, but device complexity and volume increase

Engineering Contradiction:
Improvelow-frequency noise filteringVSAvoidfilter structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines multiple filtering functions into a single integrated filter structure rather than adding separate filter circuits. The first and second filter circuits are merged into one configuration that handles both low-frequency and high-frequency noise simultaneously, reducing overall device complexity while maintaining comprehensive noise filtering capability.

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

The dual-stage filter system enhances EMC performance by effectively filtering noise signals across different frequency intervals, reducing costs and volume, and alleviating resonance effects, while maintaining optimal filtering capabilities.

Implementation Method 1

a first-stage filter circuit connected between a first pair of terminals of the DC power supply and a second pair of terminals of the inverter module, and used for filtering noise signals with frequencies within a first frequency interval and a second frequency interval

Methodology Applied
Scientific EffectElectromagnetic filtering: Filter (electronic)

Implementation Method 2

a second-stage filter circuit connected between a third pair of terminals of the first-stage filter circuit and a fourth pair of terminals of the power conversion module, and used for filtering noise signals with frequencies within the second frequency interval

Methodology Applied
Scientific EffectElectromagnetic filtering: Filter (electronic)

Data Source

PatentEP4637008A1Power conversion system and vehicle
Publication Date: 2025.10.22 VALEO ELECTRIFICATION
  • EP4637008A1 patent drawingFigure 1~2
  • EP4637008A1 patent drawingFigure 3~4
  • EP4637008A1 patent drawingFigure 5

AI summary

A power conversion system and a vehicle are provided. The power conversion system may include: a DC power supply for providing a first DC voltage; an inverter module for converting the first DC voltage into a first AC voltage; a power conversion module for converting the first DC voltage into a second AC voltage, or converting a third AC voltage from outside the power conversion system into a second DC voltage; a first-stage filter circuit connected between a first pair of terminals of the DC power supply and a second pair of terminals of the inverter module, and used for filtering noise signals with frequencies within a first frequency interval and a second frequency interval; and a second-stage filter circuit connected between a third pair of terminals of the first-stage filter circuit and a fourth pair of terminals of the power conversion module, and used for filtering noise signals with frequencies within the second frequency interval, wherein the second frequency interval is different from the first frequency interval.