Semiconductor Module Bus Bar Joining to Reduce LC Resonance
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Solution Overview
Problem
Conventional power conversion systems face challenges in minimizing inductance components between semiconductor modules, leading to increased LC resonance and potential damage to switches, especially when bus bars are indirectly connected via conductive members.
Innovation Solution
The configuration includes directly joining exposed terminals from resin-encapsulated semiconductor modules using laser welding, forming closed loops that reduce inductance components and inhibit LC resonance by connecting first and second internal bus bars directly, thereby minimizing inductance between modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bus bars are indirectly connected via conductive members between semiconductor modules, then ease of assembly is improved, but inductance components increase leading to LC resonance and potential switch damage
Solution Approach 1:
The patent merges the bus bar connection function directly into the resin encapsulation structure by forming conductive patterns on the resin member's surface. This integration eliminates the need for separate conductive members while reducing inductance, as the conductive path is formed as part of the encapsulation itself rather than as an additional component requiring indirect connection.
Solution Approach 2:
The resin member serves as an intermediary that performs dual functions: encapsulation protection and electrical connection. By forming conductive patterns directly on the resin surface, the resin acts as both the encapsulating medium and the connection pathway, eliminating the need for separate conductive members and reducing inductance components.
2Reliability
If bus bars are directly connected between semiconductor modules, then inductance components are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent combines the encapsulation function and electrical connection function into a single integrated structure. The conductive patterns are formed directly on the resin encapsulation member, merging what would traditionally be separate components (encapsulation material and conductive bus bars) into one unified element, thereby simplifying manufacturing despite achieving direct connection.
Solution Approach 2:
The patent changes the physical state and properties of the resin member by forming conductive patterns on its surface. This parameter change allows the resin to serve dual purposes: maintaining its encapsulation properties while acquiring electrical conductivity in specific regions, thereby enabling direct connection functionality without adding separate components.
3Reliability
If inductance components are reduced by direct connection, then LC resonance is inhibited, but connection precision requirements increase
Solution Approach 1:
The resin member acts as an intermediary that provides a flexible substrate for conductive patterns. This allows precise control of electrical connection paths while accommodating manufacturing tolerances, as the conductive patterns can be precisely defined on the resin surface without requiring extremely precise mechanical alignment between separate components.
Solution Approach 2:
By changing the resin member's surface properties to enable conductive pattern formation, the patent achieves precise electrical connections through material property control rather than mechanical precision. The conductive patterns can be precisely defined through printing or deposition processes on the resin surface, reducing the need for high mechanical connection precision.
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 approach effectively decreases inductance components and reduces LC resonance, protecting the semiconductor switches and enhancing the reliability of the power conversion system by directly joining exposed terminals from resin-encapsulated modules.
Implementation Method 1
The configuration includes directly joining exposed terminals from resin-encapsulated semiconductor modules using laser welding, forming closed loops that reduce inductance components
Data Source
AI summary
A first module includes a first switch having a first electrode and a second electrode; a second switch having a third electrode and a fourth electrode; a second internal bus bar connecting the second electrode with the third electrode; and a first resin member encapsulating those components. A second module with includes a third switch having a fifth electrode and a sixth electrode; a fourth switch having a seventh electrode and an eighth electrode; a fifth internal bus bar connecting the sixth electrode with the seventh electrode; and a second resin member encapsulating those components. At least one of a first terminal of the second internal bus bar exposed from the first resin member and a second terminal of the fifth internal bus bar exposed from the second resin member extends toward the other and are directly joined with each other.