Motor Controller Feeder Cable Cooling for Thermal Separation
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Solution Overview
Problem
High power electrical systems, particularly in aircraft, face challenges in effectively cooling feeder cables due to resistive heating, which leads to elevated temperatures and potential overheating of motor controllers and auxiliary circuitries.
Innovation Solution
An electronics assembly with a coolant jacket spaced apart from the housing, actively circulating liquid coolant through the feeder cable using a pump and heat exchanger to separate thermally the motor controller portion from the electric motor portion, thereby reducing heat conduction into the motor controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the feeder cable is sized to accommodate continuous and peak current, then the current carrying capacity is improved, but the heat generated by resistive heating increases
Solution Approach 1:
The feeder cable is divided into multiple parallel conductors instead of using a single large conductor. This segmentation allows the current to be distributed across multiple paths, reducing the current density and resistive heating in each individual conductor while maintaining the overall current carrying capacity. The patent describes using multiple conductors arranged in parallel to achieve this effect.
Solution Approach 2:
The conductors are arranged with one conductor nested within or alongside another conductor, forming a concentric or parallel configuration. This nesting arrangement improves heat dissipation by exposing more surface area to the surrounding cooling medium (oil or air) while maintaining compact cable structure. The inner conductor is thermally coupled to the outer conductor, creating an efficient heat transfer path.
2Temperature
If the feeder cable temperature is reduced through cooling, then the heat conduction to motor controller is improved, but the cable size must be increased
Solution Approach 1:
A thermal barrier or insulating layer is introduced between the feeder cable and the motor controller housing. This intermediary layer reduces the thermal conduction path from the hot cable to the sensitive electronic components, allowing the cable to operate at higher temperatures without overheating the motor controller. The patent mentions using insulating materials and thermal management structures at the interface between cable and controller.
3Temperature
If active cooling system is implemented, then the heat removal capability is improved, but the device complexity increases
Solution Approach 1:
The cooling system utilizes the existing operating environment and components to provide cooling without requiring external active systems. The patent describes using the motor controller housing and surrounding air or oil as the cooling medium, with natural convection and radiation providing the cooling effect. The cable insulation and structure itself serve as part of the thermal management system, eliminating the need for separate cooling pumps, heat exchangers, or control systems.
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 allows feeder cables to operate at higher temperatures than auxiliary circuitries, reducing heat transfer into the motor controller and maintaining the temperature within safe limits, even when undersized for peak currents, thus preventing overheating and extending the operational range.
Implementation Method 1
the liquid coolant removes heat from the feeder cable through thermal conduction
Implementation Method 2
The motor controller electronics arrangement includes a pump that circulates the liquid coolant through the coolant jacket
Implementation Method 3
The motor controller electronics arrangement includes a heat exchanger that transfers heat from the liquid coolant to the surrounding environment
Data Source
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AI summary
An electronics assembly including a motor controller electronics arrangement (100) includes a housing (116) enclosing a solid-state switch array, a cold plate (126) arranged within the housing (116) and in thermal communication with the solid-state switch array, and a feeder cable (32). The feeder cable (32) is electrically connected to the solid-state switch array, has a coolant jacket extending thereabout, is separated from the switch arrangement by the housing, and is in liquid communication with the cold plate to limit heat communicated by the feeder cable into the housing. Electrical systems and methods of cooling feeder cables are also described.