Rotating Rectifier Static Discharge Resistance Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotating rectifiers in aerospace applications face increased diode failure risk due to the accumulation of static charges when clean cooling oil is used, as it lacks conductive particles to dissipate static electricity, leading to potential discharges that can damage the rectifier components.
Innovation Solution
Incorporating resistance paths between bus bars and a grounded support to facilitate the conduction of static discharges, using insulating materials like polyimide film and semi-conductive elements to create paths that can clamp and compress, thereby grounding static currents and reducing the risk of damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If clean cooling oil is used, then the cooling efficiency is improved, but static charge accumulates causing diode failure
Solution Approach 1:
The patent introduces an intermediary resistance path between the diode and ground, mediated by a resistive material (such as a carbon-loaded plastic material or metal oxide varistor) that allows controlled discharge of static charges without affecting the cooling oil's cleaning and cooling functions. This intermediary element protects the diode from static discharge damage while maintaining the benefits of clean cooling oil.
Solution Approach 2:
The patent changes the electrical parameter of the connection between the diode and ground by introducing a resistance path with specific resistance value (typically 1kΩ to 10MΩ). This parameter change allows the system to tolerate static charge accumulation by providing a controlled discharge path, thereby protecting the diode while maintaining cooling efficiency with clean cooling oil.
2Reliability
If resistance paths are added to protect against static discharge, then diode reliability is improved, but parasitic losses increase
Solution Approach 1:
The patent optimizes the resistance value parameter of the resistance path to balance protection and energy loss. By selecting an appropriate resistance value (1kΩ to 10MΩ), the system achieves adequate static discharge protection while minimizing parasitic power losses, as the power loss is inversely proportional to the resistance value (P=V²/R).
Solution Approach 2:
The resistance path provides partial protection rather than complete isolation, allowing small leakage currents to flow continuously for static discharge protection while the majority of the operational current flows through the normal diode path. This partial action approach minimizes the impact on system performance while providing adequate protection.
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
The implementation of resistance paths effectively reduces the risk of diode failure by grounding static discharges, although it introduces parasitic losses, which can be minimized through appropriate design, ensuring the rectifier's reliability in aerospace environments.
Implementation Method 1
the first and second resistance paths permit the conduction of such static discharges to the support
Implementation Method 2
each bus bar is insulated from the support by a layer of an insulating material such as polyimide film
Data Source
AI summary
A rectifier comprising an electrically conductive support 32, a first plurality of rectifier components 24 carried by the support 32 and having their anodes connected to a first bus bar 26, a second plurality of rectifier components 28 carried by the support 32 and having their cathodes connected to a second bus bar 30, the cathode of each of the first rectifier components 24 being connected to the anode of an associated one of the second rectifier components 28, and first and second resistance paths 40, 42 between the first and second bus bars 26, 30 and the support 32.