Power Module Snubber Capacitor Segmentation

Solution Overview

Problem

Existing power modules face challenges in maintaining appropriate snubber capacitor capacitance due to temperature variations, leading to increased surge voltage that can exceed element breakdown voltage, requiring larger spaces and higher costs.

Innovation Solution

A power module design featuring detachable and replaceable snubber capacitors connected to shorter leads, allowing for adjustable capacitance and reduced size, enabling effective surge voltage reduction without the need for excessive space or cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a capacitor with large capacitance is embedded in the module to account for capacitance variations, then the surge voltage reduction is improved, but the module size and cost increase

Engineering Contradiction:

Improvesurge voltage reductionVSAvoidmodule size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The capacitor is divided into two separate parts: a first capacitor connected to the first power element and a second capacitor connected to the second power element. This segmentation allows each capacitor to be optimized for its specific power element, reducing the total capacitance required while maintaining effective surge voltage reduction for each element independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different capacitance values are assigned to different locations based on the specific requirements of each power element. The first capacitor has a first capacitance value optimized for the first power element, while the second capacitor has a second capacitance value optimized for the second power element, allowing localized optimization rather than using a uniformly large capacitance throughout the module.

Inventive Principle:

Principle #3Local quality

2Reliability

If a capacitor with large capacitance is embedded in the module to account for capacitance variations, then the surge voltage reduction is improved, but the module cost increases

Engineering Contradiction:

Improvesurge voltage reductionVSAvoidmodule cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The capacitor is divided into two separate parts: a first capacitor connected to the first power element and a second capacitor connected to the second power element. This segmentation allows each capacitor to be optimized for its specific power element, reducing the total capacitance required while maintaining effective surge voltage reduction for each element independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different capacitance values are assigned to different locations based on the specific requirements of each power element. The first capacitor has a first capacitance value optimized for the first power element, while the second capacitor has a second capacitance value optimized for the second power element, allowing localized optimization rather than using a uniformly large capacitance throughout the module.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If high dielectric capacitor material is used to achieve appropriate capacitance, then the capacitance is improved, but the sintering process becomes difficult and reliability decreases

Engineering Contradiction:

ImprovecapacitanceVSAvoidsintering process

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The capacitor is divided into two separate parts: a first capacitor connected to the first power element and a second capacitor connected to the second power element. This segmentation allows each capacitor to be optimized for its specific power element, reducing the total capacitance required while maintaining effective surge voltage reduction for each element independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different capacitance values are assigned to different locations based on the specific requirements of each power element. The first capacitor has a first capacitance value optimized for the first power element, while the second capacitor has a second capacitance value optimized for the second power element, allowing localized optimization rather than using a uniformly large capacitance throughout the module.

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 solution allows for optimal surge voltage reduction while minimizing apparatus size and cost, ensuring the snubber capacitors remain effective across varying temperatures.

Implementation Method 1

a snubber capacitor for reducing or eliminating surge voltage is connected to be adjacent to semiconductor switching elements

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10389229B2Power module

Publication Date: 2019.08.20 MITSUBISHI ELECTRIC CORP

AI summary

It is an object to provide a technique where a snubber capacitor having an appropriate capacitance is usable. A power module includes: a third lead having one end electrically connected to a first connection point and the other end exposed from a package, where the third lead is shorter than a first lead; and a fourth lead having one end electrically connected to a second connection point and the other end exposed from the package, where the fourth lead is shorter than a second lead. A snubber capacitor is attachable to and detachable from the other ends of the third lead and fourth lead.