Coaxial Half-Bridge Module Reducing Stray Inductance
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Solution Overview
Problem
Existing half-bridge power semiconductor modules face challenges in minimizing stray inductance in interconnections, which limits switching frequencies and efficiency in applications like electric vehicles.
Innovation Solution
A half-bridge module design featuring a substrate with divided metallization layers for DC and AC areas, coaxial terminal arrangements, and a bridging element to distribute load current, reducing commutation loop stray inductance and enabling higher switching frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional terminal arrangements are used in half-bridge modules, then the structure is simple and easy to manufacture, but the stray inductance in interconnections is high, limiting switching frequencies
Solution Approach 1:
The patent implements a nested terminal arrangement where inner DC terminals are positioned coaxially between outer DC terminals. The inner terminals are electrically connected to the AC conducting area, while outer terminals connect to DC conducting areas. This nested configuration creates overlapping current paths that cancel magnetic fields, reducing stray inductance and enabling higher switching frequencies without excessive structural complexity
Solution Approach 2:
The patent transitions from a planar terminal arrangement to a three-dimensional coaxial configuration. By arranging terminals in multiple layers (inner and outer terminals at different radial positions) and connecting them through vertically stacked conducting areas on the substrate, the invention utilizes the third dimension to optimize current path geometry and minimize inductance
2Productivity
If the commutation loop area is reduced to lower stray inductance, then switching frequency increases, but the terminal arrangement becomes more complex
Solution Approach 1:
The nested coaxial terminal arrangement naturally minimizes commutation loop area by positioning return current paths (inner terminals) inside the forward current paths (outer terminals). This concentric configuration ensures that current loops are as small as possible, reducing stray inductance and enabling high switching frequencies
Solution Approach 2:
The terminal arrangement is segmented into functionally distinct inner and outer terminals with separate electrical connections to different conducting areas. This segmentation allows independent optimization of current paths for forward and return currents, minimizing the commutation loop area while maintaining a systematic rather than chaotic structure
3Productivity
If coaxial terminal arrangement is implemented to reduce stray inductance, then switching frequency increases, but manufacturing complexity increases
Solution Approach 1:
The nested coaxial terminal structure is integrated into the substrate's conducting area layout, allowing simultaneous formation of inner and outer terminals during standard PCB or leadframe manufacturing processes. The conducting areas are designed as stacked layers that naturally guide terminal positions, reducing the need for post-assembly adjustments
Solution Approach 2:
The patent merges the terminal arrangement design with the substrate's conducting area configuration. The inner and outer DC terminals are electrically connected to conducting areas that are part of the same substrate structure, consolidating multiple functions (current distribution, terminal support, electrical connection) into a single integrated component rather than separate assemblies
Data Source
AI summary
A half-bridge module includes a substrate with a base metallization layer divided into a first DC conducting area, a second DC conducting area and an AC conducting area; at least one first power semiconductor switch chip bonded to the first DC conducting area and electrically interconnected with the AC conducting area; at least one second power semiconductor switch chip bonded to the AC conducting area and electrically interconnected with the second DC conducting area; and a coaxial terminal arrangement including at least one inner DC terminal. The at least first outer DC terminal and the at least one second outer DC terminal protrude from the module and are arranged in a row, such that the at least one inner DC terminal is coaxially arranged between the at least one first outer DC terminal and the at least one second outer DC terminal.