Permanent Magnet Synchronous Reluctance Motor Asymmetric Rotor Design

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Solution Overview

Problem

Existing technologies have not effectively addressed the challenges of electromagnetic vibration noise, harmonic loss, and efficiency issues in permanent magnet assisted synchronous reluctance motors, particularly in self-starting permanent magnet assisted reluctance motors.

Innovation Solution

A permanent magnet assisted synchronous reluctance motor design with a specific stator and rotor structure, including a rotor core with axially stacked magnetic laminations, and conductor slots, and magnet slots, where the positional relationship between the d-axis and q-axis is set to reduce the harmonic loss and efficiency issues in the magnetic conduction channels, and the stator structure with alternating stator teeth and slots, and the end ring structure, to reduce cogging harmonics and improve the sinusoidal quality of the current waveform.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple magnetic conduction channels are used in the rotor, then the motor can achieve self-starting capability and higher power density, but the magnetic field and input current harmonics increase significantly, leading to electromagnetic vibration noise

Engineering Contradiction:
Improvepower densityVSAvoidelectromagnetic vibration noise
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetry by setting different alignment relationships for d-axis and q-axis with respect to stator teeth and slots. The d-axis is aligned with stator tooth centerlines while the q-axis is staggered, creating an asymmetric magnetic conduction channel arrangement that reduces harmonics while maintaining self-starting capability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by optimizing the magnetic conduction channel distribution specifically in the q-axis direction, where channels are arranged to avoid alignment with stator teeth, thereby locally reducing harmonic generation in critical areas while maintaining overall motor performance

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If conventional rotor structure is used, then manufacturing is simpler, but cogging harmonics are significant and current waveform quality is poor

Engineering Contradiction:
Improve rotor structure manufacturingVSAvoidcogging harmonic reduction
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the rotor magnetic conduction channels into distinct d-axis and q-axis groups with different geometric arrangements. This segmentation allows each group to be optimized independently for its specific function while maintaining manufacturability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by pre-configuring the magnetic conduction channel positions and orientations during rotor manufacturing to ensure proper alignment relationships with stator teeth and slots, thereby reducing cogging harmonics before the motor operates

Inventive Principle:
Principle #10Preliminary 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

The design effectively reduces electromagnetic noise and harmonic loss, enhances motor efficiency, and improves starting capability by optimizing the conductor slot area and magnetic conduction channel arrangement.

Implementation Method 1

Magnet steels are able to provide a strong magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

magnet steels disposed in the plurality of layers of the permanent magnet slots

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 3

It utilizes asynchronous torques generated by rotor bars to achieve self-starting

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

a rotor core including a plurality of axially stacked magnetic conductive laminations

Methodology Applied
Scientific EffectMagnetic conduction: Conduction (thermal)

Implementation Method 5

employing both magnet steel torques and reluctance torques

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Data Source

PatentEP4668545A1Permanent-magnet-assisted synchronous reluctance motor
Publication Date: 2025.12.24 GREE ELECTRIC APPLIANCE INC OF ZHUHAI
  • EP4668545A1 patent drawingFigure 1
  • EP4668545A1 patent drawingFigure 2~3
  • EP4668545A1 patent drawingFigure 4~5

AI summary

The present invention provides a permanent magnet assisted synchronous reluctance motor. The permanent magnet assisted synchronous reluctance motor comprises a stator structure and a rotor structure. The stator structure is sleeved outside the rotor structure and forms an air gap with the rotor structure. The rotor structure comprises a rotor core. The stator structure includes a stator core having uniformly distributed thereon a plurality of alternately arranged stator teeth and stator slots. When any d-axis centerline of the rotor structure is aligned with a stator tooth centerline of the stator structure, a d-axis centerline adjacent to the d-axis centerline is aligned with a stator slot centerline, and a q-axis centerline adjacent to the d-axis centerline is staggered with the stator tooth centerline or the stator slot centerline. The permanent magnetpermanent magnet assisted synchronous reluctance motor according to the present invention can effectively reduce the cogging effect, reduce the noise and harmonic loss, and improve the motor efficiency.