Diode Module Breakage Containment in Power Converters

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Solution Overview

Problem

Existing power converters with diode modules face reliability issues when destruction occurs, causing broken pieces to scatter outside the module case, which can deteriorate the reliability of external equipment.

Innovation Solution

The power converter incorporates a diode module with a breakage prevention structure on at least one exterior wall face of the module case, directing destruction to a nonplacement area farther from the body case slits, thereby preventing debris from escaping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external protective devices (fast-blow fuses) are inserted in series with at least two phases of the three-phase AC to prevent excessive current flow during short circuit breakdown, then the reliability of the power converter is improved, but the cost and physical space increase

Engineering Contradiction:

Improvereliability of power converterVSAvoidcost and physical space

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the protective function from external devices and integrates it into the diode module itself through the breakage prevention structure. This eliminates the need for external fast-blow fuses, reducing both cost and physical space while maintaining reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The breakage prevention structure acts as an intermediary element within the diode module that prevents catastrophic failure. It mediates between the semiconductor diodes and the module case, containing debris internally rather than requiring external protective devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a fibrous reinforcing member is wound at the outer circumference of a frame surrounding a semiconductor chip to prevent broken pieces from scattering, then the reliability of the semiconductor device is improved, but broken pieces can still scatter out of the power converter

Engineering Contradiction:

Improvereliability of semiconductor deviceVSAvoidscattering of broken pieces

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention segments the protective function into two parts: the fibrous reinforcing member prevents chip fragmentation, and the breakage prevention structure on the module case prevents debris ejection. This layered segmentation ensures comprehensive containment of broken pieces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The breakage prevention structure provides beforehand cushioning by being positioned on the module case to receive and contain debris before it can scatter outside the power converter. This preventive measure is in place before any failure occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If the breakage prevention structure entirely covers the counter face, then the protection against module case breakage is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improveprotection against module case breakageVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention applies local quality by positioning the breakage prevention structure specifically on the counter face (or largest noncounter face) where it is most needed for debris containment. This targeted approach provides maximum protection while minimizing manufacturing complexity compared to complete coverage.

Inventive Principle:

Principle #3Local quality

4Object-affected harmful factors

If the breakage prevention structure is disposed on the noncounter placement face with largest area, then the containment of broken pieces is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvecontainment of broken piecesVSAvoidmanufacturing precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The invention applies partial action by disposing the breakage prevention structure on the noncounter placement face with the largest area, which provides sufficient containment for broken pieces. This strategic positioning achieves effective debris containment without requiring precise positioning on all faces.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12206336B2Power converter

Publication Date: 2025.01.21 MITSUBISHI ELECTRIC CORP

AI summary

A converter includes a diode module including a diode bridge disposed inside a module case; and a body case including an opening in a placement face. The module case includes a counter face facing the placement face and a noncounter face, with a breakage prevention structure being disposed on at least one of the counter face or the noncounter face. When the counter face is where the breakage prevention structure is disposed, the breakage prevention structure entirely covers the counter face. When the noncounter face is where the breakage prevention structure is disposed, the noncounter face where the breakage prevention structure is disposed is a noncounter placement face with a largest area among exterior wall faces of the module case, and the noncounter placement face including an area farther from the placement face than a middle of the noncounter placement face is as a nonplacement area.