Rotating Electrical Machine Magnet Layout for Flux Saturation Control
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Solution Overview
Problem
Typical rotating electrical machines face challenges in increasing surface magnetic flux density of the rotor to enhance torque output due to magnetic saturation and eddy-current losses, which restrict the effective employment of magnetic flux.
Innovation Solution
The design incorporates a cylindrical magnet unit with alternately arranged magnetic poles, an armature winding with a specific dimension ratio, and conductive members made of bundled wires, optimizing magnetic flux interlinking to minimize leakage and eddy-current losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets with high remanent flux density are used to increase surface magnetic flux density of the rotor, then torque output is enhanced, but magnetic saturation occurs in the stator causing leakage of magnetic flux
Solution Approach 1:
The patent applies local quality by varying the magnetization direction angles in different regions of the permanent magnets. Specifically, the magnetization direction angle is set to 90 degrees in a first region and a different angle (not equal to 90 degrees) in a second region, allowing different parts of the magnet to have different magnetic characteristics. This enables the rotor to maintain high surface magnetic flux density while controlling the magnetic flux distribution to prevent stator saturation and leakage.
2Power
If surface magnetic flux density of the rotor is increased to enhance torque output, then eddy-current loss in the stator winding increases
Solution Approach 1:
The patent applies local quality by varying the magnetization direction angles in different regions of the permanent magnets. Specifically, the magnetization direction angle is set to 90 degrees in a first region and a different angle (not equal to 90 degrees) in a second region, allowing different parts of the magnet to have different magnetic characteristics. This enables the rotor to maintain high surface magnetic flux density while controlling the magnetic flux distribution to prevent stator saturation and leakage.
3Ease of manufacture
If conventional magnet orientation is used, then manufacturing is simple, but magnetic flux leakage and eddy-current loss occur
Solution Approach 1:
The patent applies local quality by varying the magnetization direction angles in different regions of the permanent magnets. Specifically, the magnetization direction angle is set to 90 degrees in a first region and a different angle (not equal to 90 degrees) in a second region, allowing different parts of the magnet to have different magnetic characteristics. This enables the rotor to maintain high surface magnetic flux density while controlling the magnetic flux distribution to prevent stator saturation and leakage.
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 improves surface magnetic flux density, reduces magnetic saturation and eddy-current losses, and effectively enhances torque output by increasing magnetic flux interlinking with conductive members.
Implementation Method 1
a cylindrical magnet unit, the magnet unit having a plurality of magnetic poles having North and South polarities which are alternately arranged in a circumferential direction of the magnet unit
Implementation Method 2
an armature which is equipped with a multi-phase armature winding
Data Source
AI summary
A rotating electrical machine includes a magnetic field-producing unit, an armature with a multi-phase armature winding, and a rotor. The magnetic field-producing unit includes a first portion and a second portion. The first portion is located closer to a d-axis in a d-q axis coordinate system than the second position is. The second position is located closer to a q-axis in the d-q axis coordinate system than the first position is. The magnetic field-producing unit is magnetically oriented to meet a condition where an angle which an easy axis of magnetization of the first portion makes with the d-axis is smaller than an angle which an easy axis of magnetization of the second portion makes with the q-axis. The magnetic field-producing unit is configured to have an intrinsic coercive force of 400 kA/m and also have a remanent flux density of 1.0 T or more.