Slit Heatsink Structure for Lower Eddy Current Motor Cooling
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Solution Overview
Problem
Existing cooling systems for high-power density electric motors, such as those used in aerospace applications, face challenges in reducing eddy current losses and maintaining copper fill factor and stator flux while using liquid cooling methods that involve conduits through windings or stator teeth.
Innovation Solution
A heatsink with a heat spreader featuring channels and slits or surface treatments to reduce eddy currents, which is positioned in proximity to the motor windings, includes a coolant inlet and outlet, and is made from materials like aluminum, Monel, or stainless steel with optimized slit configurations to minimize eddy current losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conduits are run through the stator teeth for cooling, then cooling effectiveness is improved, but stator flux is reduced and eddy current losses increase
Solution Approach 1:
The heatsink is segmented into multiple sections with slits that divide the continuous structure into discrete regions. This segmentation interrupts eddy current paths while maintaining thermal conductivity through the remaining material, reducing eddy current losses by over 20% while preserving cooling effectiveness.
Solution Approach 2:
The heatsink incorporates localized surface features and slits in specific regions to reduce eddy currents without compromising overall thermal performance. The slits are strategically positioned to interrupt eddy current loops while maintaining adequate heat transfer areas, achieving selective property modification.
2Temperature
If conduits are run through the windings for cooling, then direct cooling is improved, but copper fill factor is reduced
Solution Approach 1:
The cooling function is extracted from the winding structure itself and placed in a separate heatsink component positioned adjacent to the windings. This eliminates the need to route conduits through the windings, maintaining copper fill factor while providing effective cooling through the heatsink's channel system.
3Power
If solid heatsink material is used, then thermal conductivity is improved, but eddy current losses increase
Solution Approach 1:
The solid heatsink material is segmented by introducing slits that divide the continuous conductive path into isolated regions. This reduces eddy current loops while maintaining thermal conduction through the remaining material structure, achieving over 20% reduction in eddy current losses while preserving adequate thermal conductivity for cooling.
Solution Approach 2:
The heatsink employs a composite structure combining conductive material with non-conductive slit regions. This creates a hybrid structure that allows thermal energy transfer while blocking electrical eddy current paths, effectively decoupling thermal and electrical conductivity properties.
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 heatsink design reduces eddy current losses by over 20% and maintains thermal conductivity, thereby enhancing the motor's power density and heat transfer efficiency without compromising copper fill factor or stator flux.
Implementation Method 1
a heat spreader configured to be placed in proximity to a winding of the electric motor
Implementation Method 2
a channel formed through the heat spreader and comprising a coolant inlet and a coolant outlet
Implementation Method 3
The plurality of slits are configured to reduce eddy currents induced in the heatsink
Data Source
AI summary
A heatsink for an electric motor, the heatsink comprising a heat spreader configured to be placed in proximity to a winding of the electric motor, a channel formed through the heat spreader and comprising a coolant inlet and a coolant outlet, and a surface feature formed into a back face of the heat spreader that faces the winding and is configured to reduce eddy currents induced in the heatsink.