Half-Bridge Power Module Layout for Low Stray Inductance
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Solution Overview
Problem
Existing half-bridge power modules face challenges in minimizing stray inductance and optimizing commutation paths, which affect their performance and efficiency, especially in harsh environments and high-switching applications.
Innovation Solution
The power module design features switch elements and diodes arranged in a symmetric layout with short commutation paths, where each switch element is connected in parallel with its associated diode, and the switches are positioned next to each other to reduce stray inductance, with multiple DC terminals of alternating polarity and metallizations arranged to enhance electromagnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If switch elements and diodes are arranged in a symmetric layout with short commutation paths, then stray inductance and commutation loop inductance are reduced, but device complexity increases
Solution Approach 1:
The patent applies asymmetry by deliberately creating a symmetric layout pattern (HS-LS-LS-HS) that is asymmetric relative to conventional asymmetric arrangements. This symmetric arrangement of switch elements and diodes next to each other optimizes commutation paths and reduces stray inductance, while the systematic nature of the symmetry actually simplifies the manufacturing process compared to irregular asymmetric layouts.
2Reliability
If switch elements and diodes are positioned next to each other to reduce stray inductance, then electromagnetic properties are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the power module into distinct functional units (switch elements and associated diodes) that are positioned next to each other. Each switch element is paired with its associated diode in a modular fashion, creating repeatable units that can be manufactured with standard precision tolerances while achieving the desired short commutation paths and reduced stray inductance.
Solution Approach 2:
The patent applies local quality by optimizing the specific arrangement of switch elements and diodes in critical commutation path areas. The symmetric layout concentrates attention on local component positioning where it matters most for electromagnetic performance, while other areas of the module can accommodate standard manufacturing tolerances.
3Productivity
If multiple DC terminals with alternating polarity are used, then commutation paths are optimized and inductance is reduced, but device complexity increases
Solution Approach 1:
The patent applies equipotentiality by arranging DC terminals with alternating polarity (DC+, DC-, DC+, DC-) in a systematic pattern that creates symmetric potential distributions. This arrangement optimizes commutation paths by providing equipotential reference points close to each switch element, reducing the inductance of current loops while maintaining a regular, manufacturable terminal pattern.
Data Source
AI summary
A power module (1) comprises a first switch (2) comprising a first switch element (9) and an associated first diode (10), a second switch (3) comprising a second switch element (11) and an associated second diode (12), the first and second switches (2, 3) being electrically connected to form a half-bridge, wherein the switch elements (9, 11) and diodes (10, 12) are located next to each other, wherein the second switch element (11) and second diode (12) are located between the first switch element (9) and the first diode (10).