Trapezoidal Cooling Channels in Permanent Magnet Rotors
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Solution Overview
Problem
Large-capacity permanent magnet-type electrical rotating machines for wind power generation face challenges in efficiently cooling the rotor while maintaining low manufacturing costs, as high heat generation density requires costly cooling solutions, and existing technologies do not effectively address air-cooling during rotation.
Innovation Solution
A rotor design with a plurality of permanent magnets disposed in a rotor iron core, featuring alternately polarized magnets and trapezoidal-shaped cooling airflow channels with radial grooves to facilitate efficient air-cooling, reducing heat generation density and enabling a smaller, more cost-effective structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the body of an electrical rotating machine is enlarged to suppress heat generation density, then heat generation density is reduced, but weight and manufacturing cost increase
Solution Approach 1:
The patent applies pneumatic cooling by introducing cooling air into the rotor through air inlets, guiding it through cooling airflow channels along the magnetic flux path, and utilizing the rotating rotor to distribute cooled air to cooling outlets. This pneumatic cooling system enables effective heat removal without enlarging the machine body, thereby reducing weight while maintaining acceptable heat generation density.
2Temperature
If cooling performance is increased to handle high heat generation density, then cooling effectiveness improves, but manufacturing cost increases
Solution Approach 1:
The cooling airflow channels serve multiple functions: they guide cooling air along the magnetic flux path in the air gap, cool the permanent magnets embedded in the rotor, and utilize the rotor's rotation as the cooling mechanism itself. This multi-functional design achieves effective cooling without requiring separate, costly cooling systems.
Solution Approach 2:
The rotor's own rotation serves as the cooling mechanism. The rotating rotor naturally distributes cooling air from the inlets to the outlets and facilitates heat removal through the cooling channels, eliminating the need for external cooling systems or additional moving parts.
3Weight of stationary object
If the machine body is reduced in size to lower cost, then manufacturing cost decreases, but heat generation density increases
Solution Approach 1:
The pneumatic cooling system introduces cooling air through inlets in the rotor, guides it through cooling channels along the magnetic flux path in the air gap, and expels it through outlets. This enables compact machine design with effective heat removal, maintaining acceptable heat generation density without requiring a large machine body.
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 design effectively suppresses temperature rise in the permanent magnet rotor and stator, allowing for efficient cooling of the electrical power generator while maintaining a compact and economically viable structure, thereby enhancing the cooling performance and reducing manufacturing costs.
Implementation Method 1
a cooling airflow channel is provided between each pair of adjacent opposite poles
Implementation Method 2
The present invention provides a rotor that is structured so as to be suitable for being air-cooled while the rotor is rotating
Data Source
AI summary
A permanent magnet electrical rotating machine having a permanent magnet rotor and a stator, wherein:a plurality of permanent magnets are disposed in a rotor iron core of the permanent magnet rotor along a periphery of the rotor iron core, polarities thereof being alternately changed;a cooling airflow channel is formed between each pair of adjacent opposite poles on the rotor iron core; and the cooling airflow channel has an approximately trapezoidal shape on an outer periphery side of the rotor iron core; and extends from an end on a central side in a radial direction of the approximately trapezoidal shape to a radial center.