Stator Coil Layout for Coil-End Heat Dissipation
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Solution Overview
Problem
Conventional electric motor stators face inefficiencies in heat dissipation at the coil-end part, leading to increased temperature rises and reduced efficiency, particularly when using different types of windings, which complicates the reduction of heat generation and dissipation.
Innovation Solution
A stator design incorporating a stator core with a coil wound using both copper and aluminum wire windings, where the copper winding is larger in diameter and has lower electrical resistivity, connected in parallel, with a specific configuration that enhances heat dissipation efficiency by optimizing cross-sectional areas and heat loss distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum wire coil is used to reduce costs and weight, then cost and weight are reduced, but heat dissipation efficiency from coil-end part becomes insufficient
Solution Approach 1:
The patent applies local quality by using different materials (copper and aluminum) for different parts of the coil windings. Specifically, the first winding uses copper wire while the second winding uses aluminum wire, allowing each material to be optimally positioned based on its thermal and electrical properties. This resolves the contradiction by locally utilizing copper's superior heat dissipation capability where needed while maintaining overall weight reduction through aluminum usage.
Solution Approach 2:
The patent employs composite materials by combining copper and aluminum windings in a single coil structure. The coil includes both first windings (copper) and second windings (aluminum) that are electrically connected in parallel. This composite approach allows the system to benefit from both materials' properties: copper provides excellent heat dissipation and electrical conductivity, while aluminum contributes to weight reduction and cost efficiency.
2Power
If current is increased to achieve same power in size-reduced motor, then power density increases, but temperature rise of coil increases
Solution Approach 1:
The patent addresses this contradiction by strategically positioning copper windings (with superior heat dissipation) in specific locations within the coil structure. The first windings made of copper are arranged to handle high current density regions, while aluminum windings are positioned in areas where weight reduction is prioritized. This local differentiation allows the motor to achieve high power density without uniform temperature increase throughout the coil.
Solution Approach 2:
The composite copper-aluminum winding structure enables the motor to sustain higher current densities required for increased power output. The copper portions efficiently dissipate heat generated in high-current regions, while aluminum portions contribute to overall current carrying capacity with reduced weight. This material combination resolves the contradiction between power density and temperature rise.
3Temperature
If coil-end part is exposed to outside for heat dissipation, then heat dissipation path is improved, but heat dissipation efficiency remains insufficient with conventional techniques
Solution Approach 1:
The patent enhances heat dissipation efficiency by concentrating copper windings (with higher thermal conductivity) in the coil-end portions that are exposed to the outside environment. The cross-sectional area ratio condition ensures that copper windings are strategically positioned where heat dissipation to the external environment (refrigerant and lubricating oil) is most effective. This local optimization of material placement maximizes the utilization of the exposed coil-end surface for heat dissipation.
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 configuration significantly enhances heat dissipation efficiency, reducing temperature rises and improving the power output of the electric motor by effectively managing heat loss and maintaining mechanical strength.
Implementation Method 1
heat generated in the coil is preferably dissipated from the coil-end part exposed to the outside of the coil
Implementation Method 2
The calorific volume of the coil depends on the level of electrical resistance, and thus, electrical resistance of the coil is preferably low in order to reduce heat generation of the coil
Data Source
AI summary
A stator includes a stator core and a coil wound around the stator core. The coil includes at least one first winding and at least one second winding connected to the first winding in series. The stator satisfies (C1/S1)>(C2/S2), where S1 is a total cross-sectional area on a first side of a coil-end part of the coil, S2 is a total cross-sectional area on a second side of the coil-end part, C1 is a total cross-sectional area of the first winding on the first side, and C2 is a total cross-sectional area of the first winding on the second side.