Stator Winding Cooling Body That Avoids Parasitic Currents
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Solution Overview
Problem
Existing cooling solutions for electric machine windings, such as those described in US 2005/057106 A1, DE 10 2012 217 778 A1, and EP 2 985 885 A1, fail to effectively dissipate heat without inducing parasitic currents or altering the magnetic properties of the stator, leading to reduced efficiency and power output, especially in high-power density applications.
Innovation Solution
A cooling device made of a material with high thermal conductivity, low electric conductivity, low magnetic permeability, and mechanical strength, integrated with the stator windings to directly exchange heat without altering the inductance or inducing parasitic currents, using a refrigerant duct for efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling elements are inserted between stator windings to dissipate heat, then heat dissipation capability is improved, but parasitic currents are induced and magnetic properties are altered
Solution Approach 1:
The patent changes the material parameters of the cooling element by selecting materials with specific thermal conductivity, electrical conductivity, and magnetic permeability characteristics. This allows the cooling element to dissipate heat effectively while minimizing parasitic currents and magnetic interference through careful parameter selection.
Solution Approach 2:
The patent employs composite material structures for the cooling element, combining materials with different thermal, electrical, and magnetic properties. This composite approach enables simultaneous optimization of heat dissipation performance and electrical/magnetic compatibility, resolving the contradiction between thermal and electromagnetic requirements.
2Temperature
If stator size is increased to provide more surface area for heat dissipation, then heat dissipation is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent transitions from external heat dissipation (increasing stator surface area) to internal heat dissipation (inserting cooling elements within the stator structure). This dimensional shift allows heat dissipation to occur internally without increasing the overall device footprint, effectively resolving the contradiction between heat dissipation area and device size.
Solution Approach 2:
The cooling elements are nested within the stator windings structure, with cooling bars positioned in the spaces between windings. This nesting approach maximizes the use of internal space for heat dissipation without increasing the external dimensions of the stator, thereby improving heat dissipation while maintaining compact device complexity.
3Temperature
If high thermal conductivity material is used for cooling elements, then heat dissipation is improved, but electric conductivity increases causing parasitic currents
Solution Approach 1:
The patent carefully selects and adjusts material parameters to achieve the desired balance. By choosing materials with specific thermal conductivity values and corresponding electrical conductivity characteristics, the cooling element optimizes heat dissipation while keeping parasitic currents within acceptable limits through parameter optimization.
Solution Approach 2:
The patent applies different material properties to different regions or aspects of the cooling element. The material is selected to have high thermal conductivity for effective heat dissipation, while its electrical conductivity is controlled to be sufficiently low to prevent parasitic currents, creating local quality differentiation between thermal and electrical performance.
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 solution maintains the electric machine's performance by effectively dissipating heat, preventing conductor insulation degradation, and reducing parasitic currents, thereby enhancing efficiency and power output.
Implementation Method 1
a body (31) made of a material having greater thermal conductivity than the material of the main portion (11) of the stator
Implementation Method 2
an extremely high electric resistivity (an electric insulator), so as to not induce any losses due to parasitic currents
Implementation Method 3
a very low magnetic permeability, so as to not substantially alter the inductance of the winding with which said device is in thermal exchange
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a cooling device (3) for an electric machine that includes a stator (1) and at least one winding (2a-2i) coupled to said stator (1), comprising a body (31) that can be put in thermal exchange with said at least one winding (2a-2i), wherein said body is made of a material having greater thermal conductivity than the material of the stator (1) and having sufficient electric resistivity and magnetic permeability to not substantially alter the inductance of the winding with which said body (31) is in thermal exchange.