Bus Bar Stacking Reduces Stray Inductance in Power Modules
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Solution Overview
Problem
The existing semiconductor devices face challenges in reducing stray inductance and space requirements for electrical connections, which can lead to complex wiring and potential damage to insulating members due to heat when bus bars are connected.
Innovation Solution
A power conversion apparatus is designed with specifically configured conductors and capacitors, where the bus bars are arranged to intersect each other in a manner that reduces stray inductance and space requirements, and includes insulating materials to prevent thermal damage during connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bus bars are arranged in a predetermined direction for power supply connection, then electrical connection is achieved, but stray inductance increases and space requirements increase
Solution Approach 1:
The bus bars are arranged in a three-dimensional stacked configuration rather than a planar predetermined direction. The first and second bus bars are positioned at different heights (Z-axis direction) and connected through vertical stretching portions, transforming a two-dimensional wiring problem into a three-dimensional solution that reduces stray inductance while maintaining compact space usage.
Solution Approach 2:
The bus bar structure employs a nested configuration where stretching portions extend vertically from horizontal extending portions, creating a compact folded arrangement. The insulating material is nested within the folded structure of the bus bars, integrating multiple components into a compact unit that reduces overall space requirements.
2Device complexity
If bus bars are connected through welding to reduce stray inductance, then stray inductance decreases, but insulating members deteriorate due to heat
Solution Approach 1:
An insulating material is introduced as an intermediary component that is integrated into the folded structure of the bus bars. This insulating material acts as a thermal barrier during welding operations, protecting other insulating members from heat damage while allowing the welding process to proceed for reducing stray inductance.
Solution Approach 2:
The bus bar connection structure is segmented into distinct functional portions: horizontal extending portions for electrical connection, vertical stretching portions for spatial arrangement, and integrated insulating material for thermal protection. This segmentation allows welding to be performed on conductive portions while insulating portions remain protected from heat damage.
3Reliability
If multiple positive and negative bus bars are drawn out in a predetermined direction, then electrical connection is achieved, but space necessary for connection increases
Solution Approach 1:
Multiple bus bars are arranged in a three-dimensional stacked configuration utilizing the Z-axis vertical direction rather than spreading them out in a two-dimensional plane. The stretching portions extend vertically to connect horizontal extending portions at different heights, achieving compact spatial arrangement that reduces the area required for electrical connections.
Solution Approach 2:
The bus bar structure employs a nested folded configuration where horizontal extending portions and vertical stretching portions are integrated into a compact three-dimensional arrangement. This nesting of conductive and insulating portions reduces the overall footprint and space required for connecting multiple positive and negative bus bars.
Data Source
AI summary
A power conversion apparatus includes a power module, a capacitor unit 23, and a first connection portion 80a. The first connection portion 80a connects a first power conversion circuit portion 31 of the power module and the capacitor unit 23 to each other. The first connection portion 80a includes a first positive electrode bus bar extending portion 83 and a second positive electrode bus bar extending portion 93 which extend along a first module case 61 and a first positive electrode bus bar stretching portion 85 and a second positive electrode bus bar stretching portion 95 which extend in a Z axis direction. The first connection portion 80a includes a first negative electrode bus bar extending portion 84 and a second negative electrode bus bar extending portion 94 which extend along the first module case 61 and a first negative electrode bus bar stretching portion 86 and a second negative electrode bus bar stretching portion 96 which extend in the Z axis direction.