E-Machine Stator Cooling Jackets With Slot-Through Winding Cooling
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Solution Overview
Problem
Existing cooling systems for electric machines, such as those described in CN107919745A, fail to effectively manage thermal resistances and reduce the thermal path between conductors and the casing liquid cooling jacket, leading to high temperatures and limited performance improvements.
Innovation Solution
An internal cooling system with a periphery liquid cooling jacket in contact with stator laminations, high conductivity matrix encapsulating head windings, and slot-through liquid cooling jacket in contact with stator slot winding turns, combined with NDE and DE liquid cooling jackets, to extract conductor and iron losses, reducing thermal resistances and thermal paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a periphery casing liquid cooling jacket is used to extract stator laminations iron losses, then the cooling coverage is improved, but the thermal resistance between conductors and cooling jacket remains high
Solution Approach 1:
A high thermal conductivity matrix material is introduced as an intermediary between the head windings and the cooling system. This matrix replaces traditional potting materials with lower thermal conductivity, creating an efficient thermal pathway that reduces thermal resistance while maintaining electrical insulation properties.
Solution Approach 2:
The cooling system employs composite material structures including the high thermal conductivity matrix combined with liquid cooling jackets. This composite approach integrates materials with different properties (thermal conductivity, electrical insulation) to simultaneously address heat transfer efficiency and electrical isolation requirements.
2Ease of manufacture
If traditional cooling systems are used with impregnated head windings, then manufacturing is simplified, but the thermal path between conductors and cooling jacket is too long
Solution Approach 1:
The high thermal conductivity matrix serves as a thermal intermediary that bridges the gap between the head windings and the cooling jacket. It maintains the structural and electrical insulation functions of traditional impregnation while dramatically improving thermal conduction, thus shortening the effective thermal path.
Solution Approach 2:
The thermal conductivity parameter of the encapsulating material is changed from traditional potting materials (low thermal conductivity) to specialized high thermal conductivity matrix materials. This parameter change enables efficient heat extraction while preserving the manufacturing simplicity of impregnated windings.
3Reliability
If high thermal conductivity materials are used to reduce thermal resistance, then heat extraction is improved, but device complexity increases
Solution Approach 1:
The high thermal conductivity matrix performs multiple functions simultaneously: it provides thermal conduction pathways, maintains electrical insulation, offers mechanical support for the windings, and enables structural integration with the cooling jacket. This multi-functionality reduces the need for separate components, thereby limiting complexity increase.
Solution Approach 2:
The cooling system merges the thermal management function with the existing structural components. The high thermal conductivity matrix is integrated into the winding encapsulation process, combining structural support and thermal management in a single element rather than adding separate cooling components.
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 integrated cooling system enhances power density and efficiency by effectively extracting conductor and iron losses, thereby increasing the performance of electric machines.
Implementation Method 1
A periphery liquid cooling jacket in contact with the stator laminations to extract stator laminations iron losses
Implementation Method 2
periphery liquid cooling jacket in contact with stator laminations to extract stator laminations iron losses
Implementation Method 3
high conductivity matrix encapsulating the head windings to extract head winding losses
Data Source
AI summary
An internal cooling system for an electric motor comprising a Drive End, DE, casing and a Non-Drive End, NDE casing, a stator with stator laminations and stator slots, head windings and stator slot winding turns, the internal cooling system comprising a first liquid cooling channel and a second liquid cooling channel, a periphery casing liquid cooling jacket connected to the first liquid cooling channel and to the second liquid cooling channel, DE and a NDE casing liquid cooling jackets configured to be established inside the DE and NDE casings, respectively, and connected to the first liquid cooling channel and to the second liquid cooling channel, respectively, and a slot-through liquid cooling jacket connected to the NDE and a DE casing liquid cooling jackets and configured to be established through the stator slots and in contact with the head windings and the stator slot winding turns to extract winding losses.