Annular Power Converter Capacitor Module Arrangement

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Solution Overview

Problem

Conventional power conversion apparatuses in rotary electric machines experience deviations in heat generation and thermal characteristics due to uneven current distribution across capacitor modules, leading to degraded performance, as capacitors with varying capacitances receive different current flows from switching modules.

Innovation Solution

The power conversion apparatus includes multiple switching modules and capacitor modules connected in parallel, with capacitor modules arranged on both sides of switching modules and having equal capacitance values, ensuring equal current distribution and heat generation across all modules, thereby suppressing deviations in heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If capacitor modules are arranged with different capacitance values to match varying current flows from switching modules, then current distribution is optimized, but heat generation deviation increases and thermal characteristics degrade

Engineering Contradiction:

Improvecurrent distribution efficiencyVSAvoidheat generation uniformity

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent changes the arrangement pattern and connection configuration of capacitor modules rather than varying capacitance values. By arranging capacitor modules in alternating sequences with switching modules and using series/parallel connection patterns, the system maintains uniform capacitance values while achieving both optimized current distribution and uniform heat generation through symmetric current paths.

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If capacitor modules are densely arranged on one side of switching modules, then space utilization improves, but current concentration occurs in specific capacitors leading to thermal imbalance

Engineering Contradiction:

Improvespace utilizationVSAvoidthermal characteristic consistency

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent uses asymmetric arrangement strategies where capacitor modules are positioned at different radial distances from the rotation axis, creating unequal current path lengths that are compensated through series-parallel connection patterns. This asymmetric spatial arrangement achieves both compact space utilization and uniform current distribution by balancing the overall circuit topology rather than relying on symmetric positioning.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent segments the capacitor modules into multiple groups with different connection configurations (series and parallel combinations). By dividing the capacitor bank into segmented groups that are differently connected to switching modules, the system achieves uniform current distribution while maintaining compact spatial arrangement, as each segment handles a portion of the total current load.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If the number of capacitor modules is reduced to simplify the apparatus, then device complexity decreases, but current distribution control and heat uniformity become more difficult to maintain

Engineering Contradiction:

Improvenumber of capacitor modulesVSAvoidheat generation equality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent designs capacitor modules with universal, standardized configurations that can be arranged in different numbers and patterns while maintaining the same functional performance. Each capacitor module is designed to be interchangeable and can be connected in various series-parallel combinations, allowing the system to achieve uniform heat generation and current distribution regardless of the total number of modules, thus simplifying the apparatus while maintaining precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 allows for uniform current control and reduced heat variation among capacitor modules, enhancing thermal characteristics and simplifying the power conversion apparatus design by equalizing heat generation and reducing the number of required capacitor modules.

Implementation Method 1

a plurality of capacitor modules CM1 to CM3 each having a capacitor 26 that suppresses high frequency oscillation occurring on the current IM due to the switching operation

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11303219B2Power conversion apparatus with annularly-arranged switching and capacitor modules

Publication Date: 2022.04.12 DENSO CORP

AI summary

A power conversion apparatus is provided in a rotary electric machine, converting a power between a DC power source and the rotary electric machine having a multiphase winding. The power conversion apparatus includes: a plurality of switching modules each having a switching element for performing switching to control a current direction of a current flowing from the DC power source to the winding; a plurality of capacitor modules each having a capacitor that suppresses high frequency oscillation occurring on the current due to the switching operation; a positive side conductor connected to a positive electrode of the DC power source; and a negative side conductor connected to a negative electrode of the DC power source.