Distributed Rotor-Stator Cooling Passages for High Power Density Motors
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Solution Overview
Problem
Conventional cooling techniques for electric machines are inefficient and limited, leading to restricted heat transfer and degraded system performance due to excessive heat generation, which can cause magnet demagnetization and component failure.
Innovation Solution
A distributed cooling system is implemented, featuring a network of cooling passages within the electric machine that directs coolant through the rotor and stator assemblies, utilizing cooling plates to enhance heat dissipation and improve thermal management by ensuring effective distribution of coolant to critical components such as magnetic elements and windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cooling techniques (passive cooling, convection cooling, fin cooling) are employed, then the structure is simple, but the cooling efficiency is limited and heat transfer is restricted
Solution Approach 1:
The cooling system is divided into multiple independent cooling channels distributed throughout the stator and rotor structures. Each channel provides localized cooling to specific high-heat-generation zones, transforming a single ineffective cooling approach into multiple targeted cooling paths that collectively achieve superior thermal management
Solution Approach 2:
Cooling channels are strategically positioned in regions with highest heat generation (stator windings, rotor magnets, laminations). The cooling intensity and channel configuration are optimized for each specific location's thermal requirements, providing non-uniform distributed cooling that matches the spatial distribution of heat sources
2Power
If increased power densities are used to meet efficiency requirements, then the machine performance improves, but heat density increases causing adverse thermal conditions
Solution Approach 1:
Cooling channels are pre-positioned within the stator and rotor structures before the machine operates at high power density. The coolant flow paths are established in advance to intercept and remove heat as it is generated in high-power regions, preventing thermal accumulation before it can cause damage
Solution Approach 2:
A coolant fluid serves as an intermediary medium between the heat-generating components (windings, magnets, laminations) and the external cooling system. The coolant absorbs heat through the distributed channels and transports it away from critical components, enabling high power density operation without excessive temperature rise
3Device complexity
If conventional cooling channels are used, then the system complexity is low, but heat transfer is restricted and system performance degrades
Solution Approach 1:
Cooling channels are nested within the existing stator and rotor structural components. The channels are integrated into the laminations and structural framework, utilizing the machine's inherent geometry rather than adding external cooling apparatus, thereby achieving enhanced cooling with minimal increase in overall system complexity
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 distributed cooling system effectively dissipates heat, enhancing the performance and reliability of electric machines by preventing adverse thermal effects like magnet demagnetization and insulation damage, thereby improving overall system performance.
Implementation Method 1
A distributed cooling system is implemented, featuring a network of cooling passages within the electric machine that directs coolant through the rotor and stator assemblies
Implementation Method 2
The distributed cooling system effectively dissipates heat, enhancing the performance and reliability of electric machines by preventing adverse thermal effects like magnet demagnetization and insulation damage
Data Source
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AI summary
An electric machine (100) including a distributed cooling system is disclosed. The electric machine includes a housing, a stator assembly (110), a rotor assembly (108), and a distributed cooling system (150). The distributed cooling system (150) comprising at least one inlet (153), a first passage (152a, 252a), a second passage (152b, 252b), and a third passage (152c, 252c). The first passage (152a, 252a) extending axially in a first direction through at least a portion of the rotor shaft (104) to direct a flow of coolant in the first direction. The second passage (152b, 252b) is fluidly coupled to the first passage extending in a second direction through at least a portion of the rotor shaft (104) between a receiving end and a distributing end. The at least one third passage (152c, 252c) is fluidly coupled to the second passage extending between a first end and a second end and distributes coolant received from the second passage to at least one of the first end or the second end into the stator assembly.