Pulse Inverter Power Module Tab Welding With Cast-Body Support
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Solution Overview
Problem
Existing pulse inverters for electric vehicle drive units are complex to produce and have high leakage inductance due to the need for separate counterholders and insufficient creepage distances.
Innovation Solution
A pulse inverter design where the intermediate circuit capacitor and power module are attached to a mounting support with contact tabs in an overlap welded connection, using a hard cast body that acts as a counterholder, reducing the need for separate components and enhancing creepage distances through a laser welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a separate counterholder is used for welding contact tabs, then the welding process can be performed, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The patent merges the counterholder function into the hard-cast body itself. The hard-cast body serves dual purposes: as the structural housing for the power module and as the counterholder for welding the contact tabs. This eliminates the need for a separate counterholder component, reducing device complexity and simplifying manufacturing.
Solution Approach 2:
The hard-cast body is designed to perform multiple functions: it houses the power electronic components, provides structural support, and serves as the welding counterholder. This multi-functionality reduces the total number of components needed in the assembly.
2Productivity
If contact tabs are welded with a separate counterholder, then welding can be performed, but the number of components increases
Solution Approach 1:
By combining the counterholder function into the hard-cast body, the patent reduces the quantity of separate components. The hard-cast body integrates multiple functions that previously required separate parts, thereby reducing assembly complexity and improving productivity.
3Volume of moving object
If contact tabs are positioned closer together, then the inverter size is reduced, but the creepage distance becomes insufficient
Solution Approach 1:
The patent applies local quality by providing creepage protection only where needed. The hard-cast body material provides sufficient creepage distance and electrical insulation in the critical areas between contact tabs and other conductive parts, while allowing other areas to be more compact. This localized approach maintains reliability without unnecessarily increasing overall volume.
Solution Approach 2:
The hard-cast body acts as an intermediary material between conductive elements. Its inherent insulating properties provide the necessary creepage distance, eliminating the need for additional insulation components while maintaining compact dimensions.
4Ease of manufacture
If a complex assembly process with separate components is used, then manufacturing flexibility is maintained, but the manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into the hard-cast body, including structural support, component housing, and welding counterholder. This consolidation simplifies the manufacturing process by reducing the number of assembly steps and components, while maintaining manufacturing flexibility through the modular power module design.
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
Simplifies production, reduces leakage inductance, and provides sufficient clearance/creepage distances, improving the overall efficiency and reliability of the pulse inverter.
Implementation Method 1
which is created, for example, in a laser welding process
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a pulse inverter and a power module (5) for such a pulse inverter. The power module (5) has a hard-cast body (7) in which the power module tab (11) is cast, which can be joined to a tab (19, 39) leading to an intermediate circuit capacitor (3) by overlap welding. According to the invention, the power module tab (11) is supported on its side opposite the tab (19, 39) on a load-bearing hard-casting material of the hard-cast body (7), which acts as a counter-support (27) during the welding process.