Eccentric End-Winding Cover for Uniform Stator Cooling
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Solution Overview
Problem
Stator windings in high-power motors are a primary heat source, posing challenges in cooling system design, leading to temperature control issues that affect motor efficiency and safety.
Innovation Solution
An eccentric annular cover system is used to cool stator end windings, featuring a variable radial width cavity with an inlet and outlet, allowing for controlled fluid flow and eccentricity adjustments to maintain consistent heat transfer and reduce temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional cooling system with uniform cavity width is used, then the structure is simple and easy to manufacture, but the temperature distribution across windings is non-uniform and pressure drop is high
Solution Approach 1:
The cavity width in the annular cover is designed to be non-uniform, creating an asymmetric flow path where the radial distance between the cooling fluid passage and the winding varies angularly. This asymmetric geometry causes the cooling fluid velocity to vary correspondingly, achieving more uniform heat removal across different angular positions of the winding while maintaining a relatively simple single-piece cover structure.
Solution Approach 2:
Different angular sections of the cavity are designed with different radial widths to match the local cooling requirements of the winding at those positions. The cavity width is locally adjusted so that sections of the winding requiring more cooling receive higher fluid velocity, while sections requiring less cooling receive lower velocity, creating a locally optimized cooling distribution.
2Temperature
If cooling fluid velocity is increased to improve heat transfer, then cooling effectiveness increases, but pressure drop and hydraulic losses increase
Solution Approach 1:
The cavity width parameter is varied angularly to change the flow cross-sectional area at different positions. This parameter variation allows the system to achieve higher cooling effectiveness in critical areas without requiring a uniform increase in fluid velocity throughout the entire circuit, thereby reducing overall pressure drop and hydraulic losses while maintaining effective cooling where needed.
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 system effectively reduces temperature spread across windings, enabling higher motor performance with increased current capacity and efficiency, while minimizing pressure drop and hydraulic losses.
Implementation Method 1
a cover for the one or more end windings and disposed around the rotor, wherein the cover is configured to transfer a cooling fluid to cool the one or more end windings
Implementation Method 2
a first radial width of the cavity at the inlet is greater than a second radial width of the cavity at the outlet
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A system may include a rotor, a stator disposed around the rotor, the stator includes a stator core and windings, the windings include end windings extending from a longitudinal end of the stator core. A system may include a cover for the end windings and disposed around the rotor, the cover is configured to transfer a cooling fluid to cool the end windings, and the cover includes: a body to cover the end windings, the body including a cavity for the cooling fluid, an inlet disposed in the body for the cooling fluid to enter the cavity; and an outlet disposed in the body for the cooling fluid to exit the cavity, the outlet is disposed at a portion of the body opposite to the inlet, a first radial width of the cavity at the inlet is greater than a second radial width of the cavity at the outlet.