Vehicle Power Module Assemblies With Stacked DC Leadframes
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Solution Overview
Problem
In power module assemblies for automotive vehicles, existing designs face challenges with stray inductance issues that lead to voltage spikes and increased switching losses during current flow, particularly in high-voltage applications.
Innovation Solution
The proposed solution involves a vehicle power module assembly with a pair of stacked DC leadframes of opposite polarity, spaced apart to cancel parasitic inductances, and a frame design that includes specific slots for DC and AC leadframes and signal pins, optimizing the distance between the leadframes within a range of 0.1 to 20 millimeters to minimize stray inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If DC leadframes are placed close together to reduce space, then device compactness is improved, but parasitic inductance increases causing voltage spikes and switching losses
Solution Approach 1:
The patent applies asymmetry by positioning the DC leadframes at non-uniform distances from the reference plane, with one leadframe closer than the other. This asymmetric configuration creates opposing magnetic fields that cancel each other, reducing parasitic inductance while maintaining compact dimensions. The leadframes are spaced within 0.1-20mm but not equally, achieving both compactness and reduced energy loss.
Solution Approach 2:
The patent converts the harmful effect of close leadframe spacing (which normally increases parasitic inductance) into a beneficial effect by deliberately positioning them asymmetrically. The close proximity that would normally create strong inductive coupling instead creates opposing magnetic fields that cancel each other, transforming the harmful inductance into a benefit for reducing voltage spikes and switching losses.
2Loss of energy
If DC leadframes are spaced apart to reduce parasitic inductance, then switching losses are reduced, but device volume increases
Solution Approach 1:
The patent applies local quality by creating different spacing relationships for different parts of the leadframe structure. Rather than uniformly spacing all components, the DC leadframes are positioned with specific asymmetric spacing (0.1-20mm) relative to the reference plane and each other, while other components like AC leadframes and signal pins have their own optimized spacing. This localized optimization reduces overall device volume while achieving the goal of reduced parasitic inductance.
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 configuration reduces stray inductance, minimizing voltage spikes and switching losses, thereby enhancing the efficiency and reliability of power module operations in electrified vehicles.
Implementation Method 1
The spacing between the leadframes is such that parasitic inductances associated with current flowing through each of the leadframes at least partially cancel one another
Data Source
AI summary
A vehicle power stage assembly is disclosed which may include a power stage housing, a power stage supported by the housing, and a pair of stacked DC leadframes. The pair of stacked DC leadframes are of opposite polarity and spaced apart from one another. Each of the DC leadframes may extend from the power stage and each has distal and proximal ends. The spacing between the leadframes may be such that parasitic inductances associated with current flowing through each of the leadframes at least partially cancel one another. Each of the leadframes may define a first and second side surface opposite one another. The first side surfaces may be coplanar and the second side surfaces may be coplanar. A distance between the spaced apart pair of DC leadframes may be based on a preselected amount of current and a material of the DC leadframes.