Electric Machine Rotor Cooling via Inserted Heat-Conducting Elements
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cooling systems for large electrical machine rotors are inefficient and costly, particularly for non-salient machines with solid rotor iron, as they require complex cooling channels and limited cooling surfaces, leading to high production costs and insufficient cooling of rotor windings.
Innovation Solution
The active part of the electrical machine incorporates highly thermally conductive elements in the groove sides of the teeth, separating magnetic flux and heat flow conduction, allowing for effective thermal conductivity and temperature equalization along the axis of rotation, and features open recesses to accommodate heat-conducting materials that enhance waste heat removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If complex cooling channels are used to cool the rotor winding, then cooling effectiveness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the heat conduction function from the magnetically permeable tooth material and replaces it with dedicated heat-conducting elements made of highly thermally conductive materials (such as copper or aluminum). These elements are inserted into recesses in the tooth, separating the magnetic flux conduction (performed by the tooth) from the heat flow conduction (performed by the inserted elements). This extraction principle resolves the contradiction by providing effective cooling without requiring complex cooling channels within the rotor structure.
Solution Approach 2:
The patent employs composite construction by combining magnetically permeable tooth material with inserted heat-conducting elements of different materials (e.g., copper, aluminum, or copper alloys). This composite approach allows each material to perform its optimal function: the magnetically permeable material handles magnetic flux, while the highly thermally conductive inserted elements handle heat removal. This resolves the contradiction by achieving effective cooling through material composition rather than structural complexity.
2Temperature
If cooling surface area is increased to improve cooling, then temperature control is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent applies local quality by placing heat-conducting elements specifically in the tooth regions where heat generation is highest (near the winding slots), rather than uniformly increasing cooling surface area throughout the rotor. The heat-conducting elements are positioned to create localized high-performance thermal pathways from the winding to the rotor surface, achieving effective cooling at critical locations without requiring extensive cooling surface modifications that would increase manufacturing cost.
3Temperature
If cooling channels are added to cool the winding, then cooling effectiveness is improved, but the active part structure becomes more complex
Solution Approach 1:
The patent segments the heat conduction function from the overall tooth structure by inserting discrete heat-conducting elements into recesses within the tooth. Rather than creating integrated cooling channels throughout the active part, the solution uses separate, modular heat-conducting elements that can be independently positioned and optimized. This segmentation resolves the contradiction by providing effective winding cooling without requiring complex integrated cooling channel structures in the active part.
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 reduces the temperature of the electrical winding, enabling higher torque density and cost-effective cooling, allowing for operation at higher speeds and outputs, and simplifies the cooling process by eliminating the need for convective heat transfer within the active part.
Implementation Method 1
at least one heat-conducting element is provided, which has a heat-conducting material whose thermal conductivity is greater than that of the magnetically permeable material
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to an active part of an electric machine, wherein the active part comprises at least two teeth (1), which each have a magnetically permeable material and which each protrude from a lateral surface (3) of the active part in a radial direction, and at least one winding groove (4), each of which is arranged between a pair of the at least two teeth (1), wherein the at least one winding groove (4) is arranged substantially along an axis of rotation (5) of the active part and wherein an electrical winding (6) can be arranged in the particular winding groove (4). The invention further relates to an electric machine having such an active part. In order to improve the cooling of an active part economically, the active part according to the invention has at least one open recess (10, 20, 30), each of which is arranged on or in a particular tooth (1) in a particular plane, wherein the particular plane is spanned by a substantially radial direction (2) and a direction substantially along the axis of rotation, and at least one heat-conducting element (11, 21, 31), which is arranged at least partially in the particular open recess (10, 20, 30) and which has a thermally conductive material, the thermal conductivity of which is greater than the thermal conductivity of the magnetically permeable material.