Rectifier Diode Assembly With Louver Cooling for Thermal Margin
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Solution Overview
Problem
Aircraft generator rectifier assemblies face inefficient cooling, particularly under high power loads with hot cooling oil conditions, leading to low or negative thermal margins and weight issues due to existing cooling methods.
Innovation Solution
A rectifier diode assembly with bus bars and multi-contact louvers that compressively connect diodes for both thermal and electrical contact, allowing cooling oil to flow around and between the louvers for enhanced heat transfer and reduced Joule heating, eliminating the need for a dry cavity and custom diode modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional substrate-mounted diode modules with cold plates are used, then structural simplicity is maintained, but cooling efficiency deteriorates leading to low thermal margins under high power loads
Solution Approach 1:
The diode assembly is segmented into multiple individual diodes rather than a single integrated module, allowing each diode to have its own direct cooling path to the cold plate. This segmentation enables independent thermal management for each diode, improving overall cooling efficiency and thermal margins.
Solution Approach 2:
The cooling approach transitions from a single-point cold plate attachment to a multi-dimensional cooling structure with extended surfaces and thermal pathways. The cold plate incorporates thermal vias, conductive paths, and extended cooling surfaces that engage with multiple diode surfaces simultaneously, creating a three-dimensional thermal management system.
2Temperature
If fins and modifications are added to improve cooling performance, then cooling efficiency improves, but weight increases
Solution Approach 1:
The cooling structure is merged with the existing bus bar assembly and diode mounting structure. The cold plate serves dual functions as both a structural support element and a thermal management component, eliminating the need for separate fin arrays or additional cooling attachments that would increase weight.
Solution Approach 2:
The cold plate is designed as a multi-functional component that provides structural support, electrical isolation, and thermal management simultaneously. This universal design eliminates the need for dedicated cooling fins or separate mounting brackets, reducing overall assembly weight while maintaining effective cooling.
3Temperature
If substrate mounting is used, then ease of manufacture is improved, but thermal conductivity deteriorates due to intermediate thermal resistance
Solution Approach 1:
The intermediate substrate layer is extracted or eliminated from the thermal path. Diodes are mounted directly to the cold plate structure without requiring a separate substrate, thereby removing the additional thermal resistance that the substrate would introduce while maintaining manufacturing feasibility through direct attachment methods.
Solution Approach 2:
A thermally conductive intermediary material or interface layer is introduced between the diode and cold plate to enhance thermal contact. This mediator improves thermal conductivity at the interface while allowing for straightforward manufacturing processes, bridging the gap between thermal performance requirements and manufacturing simplicity.
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 solution provides efficient cooling directly at the diode level, reduces weight and size by integrating components into the generator cavity, and simplifies the system design, improving thermal margins and reducing overall system cost and complexity.
Implementation Method 1
first and second louvers... for thermally and electrically connecting the first bus bar and the diode, the second bus bar and the diode
Implementation Method 2
cooling of a rectifier diode assembly... fluid flow includes cooling fluid entering the fluid chamber for distribution about and around the first and second louvers
Data Source
Figure 1~3
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Figure 5
AI summary
A rectifier diode assembly is provided and includes first and second bus bars, a diode (130)interposed between the first and second bus bars to define first and second spaces for fluid flow between the diode (130)and the first and second bus bars, respectively, and first and second louvers (150). The first louvers (140) are compressively interposed between the first bus bar and the diode (130)to extend across the first space for thermally and electrically connecting the first bus bar and the diode. The second louvers (150) are compressively interposed between the second bus bar and the diode (130)to extend across the second space for thermally and electrically connecting the second bus bar and the diode.