Bent Permanent Magnet Rotor for Torque-Material Balance
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Solution Overview
Problem
There is a need to adjust the output characteristics of rotating electrical machines in a simple and effective manner by optimizing the dimensions of the rotor core and permanent magnets in an interior permanent magnet rotor.
Innovation Solution
A rotor design that includes a rotor core with a magnet accommodation cavity and a permanent magnet with a bent portion towards the radially inner side, where the thickness and surface area of the permanent magnet are optimized to satisfy specific expressions, allowing for the generation of sufficient magnetic and reluctance torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the permanent magnet is made thicker to generate sufficient magnetic torque, then the magnetic torque increases, but the amount of magnetic material used increases and the outer core portion for reluctance torque generation is reduced
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between the permanent magnet thickness Wm and rotor core diameter D, and between the permanent magnet surface area Sm and rotor dimensions. These parameter optimizations allow the permanent magnet to generate sufficient magnetic torque while controlling the amount of magnetic material used, resolving the contradiction between torque generation and material quantity.
2Force
If the permanent magnet surface area opposing the outer core portion is increased to generate sufficient magnetic torque, then the magnetic torque increases, but the outer core portion for reluctance torque generation is reduced
Solution Approach 1:
The patent optimizes the surface area Sm of the permanent magnet opposing the outer core portion by establishing specific mathematical relationships with rotor core diameter D, axial length L, and pole pairs P. This parameter optimization ensures sufficient magnetic torque generation while maintaining adequate outer core portion area for reluctance torque, resolving the contradiction between magnetic torque and outer core area.
3Power
If the permanent magnet dimensions are optimized to generate sufficient magnetic torque, then the output characteristics improve, but the design complexity increases
Solution Approach 1:
The patent resolves design complexity by establishing clear mathematical relationships and design guidelines for permanent magnet dimensions (thickness Wm and surface area Sm) based on rotor core parameters (diameter D, axial length L, pole pairs P). These parameter optimizations provide straightforward design criteria that improve output characteristics without significantly increasing design complexity.
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 optimized rotor design enables the generation of preferred output characteristics by ensuring sufficient magnetic torque, while also improving demagnetization resistance and reducing the amount of magnetic material used, thus enhancing the efficiency and cost-effectiveness of the rotating electrical machine.
Implementation Method 1
a permanent magnet (23) embedded in the magnet accommodation cavity of the rotor core and including a bent portion located toward a radially inner side of the rotor core, wherein the permanent magnet generates magnetic torque
Implementation Method 2
an outer core portion (25) that generates reluctance torque and is located radially outward from the permanent magnet in the rotor core
Data Source
AI summary
A rotor includes a rotor core, including a magnet accommodation cavity, and a permanent magnet, embedded in the magnet accommodation cavity of the rotor core and including a bent portion located toward a radially inner side of the rotor core. The permanent magnet has a thickness to satisfy an expression of0.0006D+0.1626−0.5/(D/2)≤Wm/(D/2)≤−0.0006D+0.1626+0.5/(D/2).