Stator Core Cavities for Heat Conduction in Electrical Machines
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Solution Overview
Problem
Existing rotating electrical machines face challenges in efficiently cooling stator windings without increasing mechanical size, as increasing linear current density to enhance torque leads to higher resistive losses, and traditional liquid cooling methods are complex and expensive.
Innovation Solution
Incorporating cavities with thermal conductors made of solid materials with higher thermal conductivity than ferromagnetic materials within the stator core structure to facilitate heat transfer from the stator teeth and windings to an external spatial room, allowing for effective cooling without the complexity of liquid cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cooling is used to cool stator windings, then cooling effectiveness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts the cooling function from the stator winding structure itself by introducing separate cooling channels in the stator core. The cooling channels are formed by removing material to create cavities, allowing coolant to flow through dedicated pathways that are separate from the electrical conductors, thus simplifying the overall system while maintaining effective cooling.
Solution Approach 2:
The invention introduces coolant as an intermediary substance to transfer heat away from the stator windings. The cooling channels provide a pathway for this intermediary coolant to flow, absorbing heat from the stator core and windings, thereby achieving effective cooling without direct contact between coolant and electrical conductors.
2Power
If linear current density is increased to enhance torque, then maximum torque is improved, but resistive losses increase
Solution Approach 1:
The invention converts the harmful heat generated by resistive losses into a manageable thermal management problem. By designing integrated cooling channels within the stator core structure, the heat that would otherwise be wasted energy is systematically removed through coolant flow, allowing higher current densities to be sustained without excessive temperature rise.
Solution Approach 2:
The invention changes the thermal parameters of the stator system by introducing cooling channels with controlled geometry, material properties, and coolant flow characteristics. This allows the stator to operate at higher current densities by adjusting thermal management parameters rather than electrical parameters, thereby maintaining torque while reducing resistive losses.
3Temperature
If cooling channels are integrated into stator core, then heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The invention segments the stator core into modular sections with cooling channels formed in each segment. The cooling channels are created by dividing the stator core into multiple parts during manufacturing, allowing each segment to be produced separately and then assembled together, which simplifies the manufacturing process while maintaining effective heat dissipation throughout the entire stator.
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 enhances heat dissipation from the stator windings, reducing resistive losses and maintaining torque without the need for complex liquid cooling systems, thus improving the efficiency and cost-effectiveness of stator cooling.
Implementation Method 1
The thermal conductor is arranged to transfer heat from the stator tooth, and thereby also from the windings, to a spatial room outside the core structure
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
A stator (100) for an electrical machine comprises stator windings (104) and a core structure (101) made of ferromagnetic material. The core structure comprises a yoke (102) and stator teeth (103) connected to the yoke. The core structure comprises cavities extending from a surface of the yoke to interiors of the stator teeth. Each cavity includes at least a part of a thermal conductor (106) made of solid material whose thermal conductivity is greater than the thermal conductivity of the ferromagnetic material. Therefore, the thermal conductor is arranged to transfer heat from the stator tooth, and thereby also from the stator windings, to a spatial room outside the core structure.