Beveled Flux-Barrier Rotor for Lower Torque Ripple in SynRM

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Traditional synchronous reluctance motors face issues with large vibration noise, low efficiency, and reduced starting capability due to torque ripple, which are not effectively addressed by existing designs.

Innovation Solution

The implementation of a direct starting synchronous reluctance motor rotor with beveled edges on the filling grooves reduces reluctance torque ripple, increases d-axis inductance, and enhances flux difference between d-axis and q-axis, thereby improving output torque and motor efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a traditional synchronous reluctance motor is used, then the motor can operate synchronously with high efficiency, but it produces large torque ripple causing vibration and noise

Engineering Contradiction:
Improvemotor efficiencyVSAvoidvibration noise
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetry by providing different fillings in the d-axis and q-axis flux barriers. The d-axis flux barrier contains a conductive filling (such as aluminum or copper) while the q-axis flux barrier contains a non-conductive filling (such as epoxy resin or plastic). This asymmetric filling configuration creates different magnetic reluctance characteristics along the d-axis and q-axis, which increases the inductance difference and thereby increases reluctance torque while reducing torque ripple, thus reducing vibration and noise while maintaining high efficiency

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If filling material reaches rotor periphery and forms part of rotor periphery, then manufacturing is simplified, but machining time increases and manufacturing cost increases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmanufacturing time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent applies segmentation by dividing the filling material into two distinct types (conductive and non-conductive) that are placed in specific regions (d-axis and q-axis flux barriers). This segmented approach allows for more efficient manufacturing processes where different filling materials can be applied separately to their respective regions, reducing overall machining time and manufacturing cost compared to forming the entire rotor periphery with a single filling material

Inventive Principle:
Principle #1Segmentation

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 design significantly reduces vibration noise, increases output torque, and enhances motor efficiency and starting capability by minimizing torque ripple and optimizing magnetic field distribution.

Implementation Method 1

a d-axis flux of the rotor core will not suddenly change when entering a stator along a channel formed at the beveled edge

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

carrying out a constant-speed running by generating a reluctance torque through a rotor inductance gap

Methodology Applied
Scientific EffectReluctance torque: Magnetic Reluctance

Implementation Method 3

realizing a start by generating a torque through a squirrel cage induction

Methodology Applied
Scientific EffectInduction torque: Electromagnetic Induction

Implementation Method 4

a filling material of a flux barrier of the rotor reaches a rotor periphery and forms a part of the rotor periphery

Methodology Applied
Scientific EffectMagnetic barrier: Magnetic Field

Data Source

PatentEP3989401B1Rotor structure of direct start-up synchronuous reluctance motor and motor
Publication Date: 2024.12.18 GREE ELECTRIC APPLIANCE INC OF ZHUHAI
  • EP3989401B1 patent drawingFigure 1
  • EP3989401B1 patent drawingFigure 2
  • EP3989401B1 patent drawingFigure 3~4b

AI summary

The present disclosure provides a direct starting synchronous reluctance motor rotor, and a motor. The direct starting synchronous reluctance motor rotor comprises: a rotor core provided with a plurality of slit grooves, two filling grooves are respectively disposed at two ends of each of the slit grooves to form a magnetic barrier layer, a first end of the filling groove being disposed adjacent to the slit groove, a second end of the filling groove being disposed to be extended outwards an outside of the rotor core, a beveled edge is disposed on the second end of at least one of the filling grooves away from a d-axis of the rotor core, so that a d-axis flux of the rotor core will not suddenly change when entering a stator along a channel formed at the beveled edge. With this arrangement, a reluctance torque ripple of the motor can be reduced, thereby reducing generated vibration noise, increasing a d-axis inductance and a flux difference between the d-axis and a q-axis, generating a greater reluctance torque, increasing an output torque of the motor with the rotor, and improving a motor efficiency.