V-Shaped Rotor Magnet Arrangement for Efficiency and Material Reduction

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Solution Overview

Problem

Permanent magnet type rotary electric machines face challenges in achieving IE4 efficiency while maintaining compatibility with current products and reducing the use of rare-earth neodymium magnets, which are costly and inefficient.

Innovation Solution

The design incorporates a rotor with permanent magnets arranged in a V shape, where the angle between the center of the rotor and the outer circumferential top of the magnets is between 0.65 and 0.80 times the number of poles, and the ratio of stator slot depth to magnet burying depth is between 0.8 and 1.1, optimizing magnetic flux counteraction and reducing magnet usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If permanent magnets are arranged in conventional patterns to achieve high efficiency, then efficiency improves, but the amount of permanent magnet material used increases

Engineering Contradiction:
ImproveefficiencyVSAvoidamount of permanent magnet
Core Design Contradiction:
Loss of energyVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating non-uniform magnetic flux distribution through specifically designed magnet arrangements. Different regions of the rotor have different magnet configurations (e.g., some magnets with polarity opposite to adjacent magnets, others with same polarity) to optimize local magnetic field characteristics. This allows efficient use of magnetic material in critical areas while reducing or eliminating magnets in less critical areas, thereby improving efficiency without proportionally increasing total magnet material usage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the rotor into multiple magnetic poles with different magnet arrangements. Each pole can have magnets configured differently (opposite polarity, same polarity, or no magnet) based on local requirements. This segmentation allows independent optimization of each pole's magnetic characteristics, enabling the system to achieve high overall efficiency while minimizing total permanent magnet material through strategic placement and omission of magnets in specific segments.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If new magnet arrangements are designed to reduce magnet usage, then material cost decreases, but compatibility with existing products and frames is lost

Engineering Contradiction:
Improveamount of permanent magnetVSAvoidcompatibility with existing products
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent achieves universality by designing a magnet arrangement system that can be adapted to existing rotor frames and stator cores while implementing reduced magnet configurations. The method allows different magnet patterns (with opposite polarity, same polarity, or no magnet) to be applied across multiple poles, creating a universal solution that maintains mechanical compatibility with standard products while achieving reduced material usage through optimized magnetic field distribution.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies parameter changes by systematically varying the magnet configuration parameters across different poles. Instead of using uniform magnet arrangements, the invention changes parameters such as magnet presence/absence, polarity orientation, and angular positioning to optimize performance. These parameter variations enable reduced magnet material usage while maintaining compatibility with existing product frameworks through careful selection of parameter combinations that fit standard geometries.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If rare-earth neodymium magnets are used for desired performance, then efficiency is achieved, but cost increases due to rare earth material

Engineering Contradiction:
ImproveefficiencyVSAvoidrare-earth material
Core Design Contradiction:
Loss of energyVSQuantity of substance

Solution Approach 1:

The patent applies partial action by implementing magnets in only certain poles or certain regions of the rotor, rather than uniformly across all poles. Specific arrangements include having some poles with magnets of opposite polarity, some with same polarity, and some with no magnets at all. This partial deployment of permanent magnets achieves sufficient magnetic field generation for high efficiency while significantly reducing the total quantity of rare-earth material required compared to full-coverage magnet arrangements.

Inventive Principle:
Principle #16Partial or excessive action

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 reduces the amount of permanent magnet usage while achieving higher efficiency and lower losses, maintaining compatibility with existing products and improving energy savings.

Implementation Method 1

permanent magnets arranged in a V shape in the rotor core to counteract a magnetic flux from the armature coil which passes between adjacent magnetic poles of the rotor

Methodology Applied
Scientific EffectMagnetic flux counteraction: Magnetic Field

Data Source

PatentEP3007323B1Rotating electrical machine in which permanent magnet is used
Publication Date: 2018.08.29 KK TOSHIBA
  • EP3007323B1 patent drawingFigure 1
  • EP3007323B1 patent drawingFigure 2
  • EP3007323B1 patent drawingFigure 3

AI summary

A permanent magnet type rotary electric machine has a stator(12), a rotor(14) which is rotatably provided inside the stator(12), and permanent magnets(26) arranged in a rotor core(24) of the rotor(14). An angle θ between a straight line(L1) connecting the center of the rotor(14) to a middle position between two permanent magnets(26) arranged in the V shape, and a straight line(L2) connecting the center of the rotor(14) to an outer circumferential top(M1) of one of the permanent magnets(26) has the relation: 0.65<Θ(=θ/(180/P))<0.80 in which P is the number of poles in the rotor(14). When a rear depth of a slot(20) of the stator core(16) is D, and a burying depth of the permanent magnet(26) in the radial direction of the rotor core (24)is t, D/t=A has the relation: 0.8<A<1.1. Elected Figure: FIG.1