Noise Removal Capacitor Positioning in Vehicle Power Conversion Modules

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Solution Overview

Problem

Current power conversion devices for vehicles face challenges in reducing noise contamination, particularly due to the susceptibility of noise removal capacitors to switching operations in the power module.

Innovation Solution

The power conversion device incorporates a noise removal capacitor within the capacitor module, electrically connected to the input-side power source terminal in a position closer to it than to the output-side power source terminal, and includes a plate-like conductor for improved electrical connections and sealing to minimize noise impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the noise removal capacitor is electrically connected to the output-side power source terminal, then the power conversion efficiency is improved, but the noise contamination increases due to susceptibility to switching operations

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidnoise contamination

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent divides the electrical connection path into two distinct paths: one connecting the noise removal capacitor to the input-side power source terminal (for noise filtering) and another path for power conversion operations. This segmentation allows the noise removal capacitor to operate independently from the switching operations, reducing noise contamination while maintaining power conversion efficiency through proper grounding and connection routing.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If the noise removal capacitor is placed closer to the output-side power source terminal, then the noise filtering effectiveness is improved, but the susceptibility to switching operations increases

Engineering Contradiction:

Improvenoise filtering effectivenessVSAvoidsusceptibility to switching operations

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces the input-side power source terminal as an intermediary connection point for the noise removal capacitor. By connecting the capacitor to the input-side terminal rather than directly to the output-side terminal, the system uses the input terminal as a mediator that provides noise filtering capability while isolating the capacitor from the high-frequency switching operations that occur at the output side, thereby reducing susceptibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the distance between the noise removal capacitor and the input-side power source terminal is increased, then the noise contamination is reduced, but the electrical connection efficiency decreases

Engineering Contradiction:

Improvenoise contaminationVSAvoidelectrical connection efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent applies local quality optimization by strategically positioning the noise removal capacitor at a specific location within the capacitor module - close enough to the input-side power source terminal to maintain low-inductance electrical connection (preserving connection efficiency), but positioned such that it effectively filters noise without being overly exposed to switching operations. The local electrical environment at this position provides optimal noise reduction while maintaining connection efficiency.

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

This configuration reduces the impact of noise contamination by making the noise removal capacitor less susceptible to switching operations, resulting in a more efficient and reliable power conversion process.

Implementation Method 1

a noise removal capacitor for removing noise

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

noise removal capacitor for removing noise

Methodology Applied

Scientific EffectElectromagnetic interference filtering: Filter (electronic)

Data Source

PatentEP2346152B1Power conversion device

Publication Date: 2018.12.12 HITACHI AUTOMOTIVE SYST LTD

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AI summary

A power conversion device for a vehicle includes: a power module that includes a switching device and, upon operation of the switching device, converts DC power into AC power to be supplied to an electric machine for driving a vehicle; a capacitor module that includes a smoothing capacitor element, an input-side power source terminal for receiving DC power, and an output-side power source terminal for supplying DC power to the power module; and a noise removal capacitor for removing noise, wherein: the noise removal capacitor is built in the capacitor module, and the noise removal capacitor is electrically connected to the input-side power source terminal in a position where a distance between a connection position of the noise removal capacitor and the input-side power source terminal is less than a distance between a connection position of the noise removal capacitor and the output-side power source terminal of the capacitor module.