Rotor Cooling Channels in Interpolar Regions
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Solution Overview
Problem
Existing rotating electrical machine rotors face inefficiencies in cooling, leading to increased heating of windings and insulators, which affects reliability and costs due to the limited heat exchange surface and high thermal resistance.
Innovation Solution
The rotor design incorporates multiple internal closed contour channels within the interpolar regions and pole shoes, increasing the heat exchange surface and turbulence, allowing for improved convective exchanges and reduced material usage, with the option to use air or other cooling fluids, and includes configurations where the cooling channels can be continuous or discontinuous, forming a serrated shape to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling channels are arranged in the rotor, then cooling effect is improved, but heat exchange surface area is limited
Solution Approach 1:
The interpolar regions are divided into multiple segments by arranging 3 to 15 internal cooling channels within each region. This segmentation of the cooling fluid flow path significantly increases the total heat exchange surface area compared to a single channel configuration, directly resolving the contradiction between limited surface area and improved cooling effect.
Solution Approach 2:
The cooling channels are arranged in a multi-dimensional configuration within the interpolar regions, utilizing the three-dimensional space available in the rotor structure. This spatial optimization maximizes the heat exchange surface area without increasing the overall rotor volume, addressing the surface area limitation.
2Temperature
If cooling channels are arranged in the rotor, then cooling effect is improved, but thermal resistance remains high
Solution Approach 1:
The cooling channels are specifically positioned within the interpolar regions where heat generation and accumulation occur. This localized cooling approach directly addresses high thermal resistance areas, improving heat dissipation efficiency and reducing temperatures where they are most critical, thereby enhancing overall thermal performance and reliability.
3Temperature
If cooling channels are arranged in the rotor, then cooling effect is improved, but quantity of active material increases
Solution Approach 1:
The interpolar regions serve multiple functions: they provide the magnetic circuit path and simultaneously house the cooling channels. This multi-functionality allows the same structural space to perform both magnetic and thermal management functions, avoiding the need for additional active material and maintaining cost-effectiveness while improving cooling.
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 design significantly enhances thermal performance, reduces the maximum temperature of electrical components, increases reliability, and lowers overall costs by optimizing heat exchange coefficients and material usage while maintaining identical thermal states compared to conventional machines.
Implementation Method 1
The rotor allows circulation of the cooling fluid along the channels. The convective exchanges are increased due to the increase in the average heat exchange coefficient.
Implementation Method 2
The presence of several internal channels increases the heat exchange surface and significantly improves the heat exchange coefficients.
Implementation Method 3
The convective exchanges are increased due to the increase in the average heat exchange coefficient. This serrated shape can be cleverly obtained by stacking identical sheets in stacks arranged in staggered rows, alternating the front and back faces of the stacks.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a rotor (1) for a rotary electric machine, extending along a longitudinal axis (X) and comprising: an assembly of electrical sheets (2) forming projecting poles (3), two projecting poles defining an interpolar region (E) therebetween; and at least two internal cooling channels (5) formed in the assembly of electrical sheets (2) in at least one interpolar region (E).