Half-Bridge Power Module Inductance Reduction via Bus Bar Nesting
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Solution Overview
Problem
Conventional half-bridge power modules have high inductance due to the commutating loop formed by power modules and capacitor banks, which degrades their performance and requires complex, costly layouts.
Innovation Solution
A mechanical layout for a half-bridge power module with power modules mounted on both sides of a heat sink and an inductance cancelling bus bar wrapped around the modules and heat sink in a loop, reducing inductance by creating a closed loop that opposes current flow in the main path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If power modules are mounted on both sides of the heat sink with bus bars connecting them, then heat dissipation is improved, but inductance increases due to the physical layout
Solution Approach 1:
The patent transitions from a conventional planar layout to a three-dimensional configuration by mounting power modules on both sides of the heat sink and wrapping the bus bar around the assembly. This spatial arrangement reduces the loop area and inductance while maintaining effective heat dissipation pathways.
Solution Approach 2:
The bus bar is wrapped around the heat sink and power modules in a nested configuration, creating a compact loop that minimizes inductance. The bus bar encircles the components rather than connecting them linearly, reducing the commutating loop area.
2Ease of manufacture
If conventional bus bar layouts are used to connect power modules, then manufacturing is simplified, but inductance becomes too high degrading performance
Solution Approach 1:
The bus bar connection method transitions from a planar layout to a three-dimensional wrapped configuration, reducing inductance while remaining manufacturable. The wrapping approach creates a compact loop that is still suitable for conventional manufacturing processes.
3Speed
If inductance is reduced through optimized layout, then switching speed is improved, but device complexity increases
Solution Approach 1:
The nested wrapping configuration of the bus bar around the heat sink and power modules achieves low inductance through a relatively simple geometric form. This compact arrangement reduces switching loop area without requiring complex multi-layer or three-dimensional printed structures.
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 significantly reduces inductance, allowing faster switching of semiconductor devices, minimizing switching losses, and simplifying the DC bus structure, leading to a more reliable and cost-effective power module with reduced complexity.
Implementation Method 1
an inductance cancelling bus bar wrapped around the heat sink, the first power module and the second power module in a loop
Data Source
AI summary
Disclosed is a mechanical layout for a half-bride power module that is optimized for low inductance. In one embodiment, a first power module and a second power module are mounted on each side of a heat sink. An inductance cancelling bus bar is wrapped around the heat sink, the first power module and the second power module in a loop.