Magnet Insertion Control for Permanent Magnet Machines

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Solution Overview

Problem

Conventional methods for assembling permanent magnet machines fail to dynamically consider potential offsets between the stator and rotor, leading to unbalanced magnetic forces and assembly issues due to unwanted magnetic attraction during the insertion process.

Innovation Solution

A control system with sensors to measure the air gap and rotor position, and a processor to determine a real-time insertion order for magnets, applying a feedback loop to adjust for changes and minimize unwanted forces, ensuring precise alignment and balanced magnetic forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional fixed-position magnet insertion method is used, then manufacturing simplicity is maintained, but unbalanced magnetic forces and assembly problems occur due to stator-rotor offset

Engineering Contradiction:
Improvemagnet insertion processVSAvoidassembly stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent transforms the static, fixed-position magnet insertion method into a dynamic process where the insertion sequence is continuously adjusted based on real-time air gap measurements. The system dynamically determines the optimal insertion sequence by considering the actual stator-rotor offset, thereby maintaining assembly stability while adapting to varying operational conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements a feedback mechanism where air gap sensors continuously measure the distance between stator and rotor, and this measurement information is fed back to the control system. The control system then adjusts the magnet insertion sequence based on this feedback, creating a closed-loop control that eliminates unbalanced magnetic forces and ensures reliable assembly.

Inventive Principle:
Principle #23Feedback

2Reliability

If real-time feedback control is implemented to adjust magnet insertion order, then assembly stability is improved, but device complexity increases

Engineering Contradiction:
Improveassembly stabilityVSAvoidcontrol system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical adjustment mechanisms with an intelligent control system that uses sensors and algorithms to determine magnet insertion sequences. Instead of physically adjusting the insertion mechanism, the system uses information processing and control logic to achieve the same effect, thereby reducing mechanical complexity while improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If magnet insertion sequence is predetermined based on pole numbers and polarity, then manufacturing speed is maintained, but unbalanced magnetic pull is generated causing structural stress

Engineering Contradiction:
Improvemagnet insertion speedVSAvoidunbalanced magnetic pull
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The patent changes the key parameter of magnet insertion from fixed positional coordinates to dynamic sequence selection based on air gap measurements. By changing how the insertion parameters are determined (from predetermined to real-time calculated), the system eliminates unbalanced magnetic pull while maintaining efficient production speeds through automated control.

Inventive Principle:
Principle #35Parameter changes

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 control system effectively mitigates unbalanced magnetic forces by dynamically adjusting the insertion order, ensuring accurate placement and minimizing assembly issues, thereby enhancing the structural stiffness and stability of the electrical machine.

Implementation Method 1

plurality of sensors which continuously measure the air gap between the rotor and the stator

Methodology Applied
Scientific EffectAir gap measurement:

Implementation Method 2

an encoder which continuously detects an angular position of the rotor

Methodology Applied
Scientific EffectAngular position detection:

Implementation Method 3

the magnets on the rotor and the coils of the stator, opposing each other, may attract each other

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Implementation Method 4

an unwanted force or unbalanced magnetic pull (UMP) may be generated in the direction of the offset

Methodology Applied
Scientific EffectUnbalanced magnetic pull:

Data Source

PatentEP3079241B1Controlled assembly of permanent magnet machines
Publication Date: 2017.11.08 GE ENERGY POWER CONVERSION TECHNOLOGY LTD(GB)
  • EP3079241B1 patent drawingFigure 1
  • EP3079241B1 patent drawingFigure 2
  • EP3079241B1 patent drawingFigure 3

AI summary

Provided is a control method and a control system (200) for controlling the insertion of a plurality of magnets (110) within an electrical machine (100) including a stator (102) and a rotor (104) which rotates in relation to the stator around a rotary axis (Ra). The control system (200) has plurality of sensors (205) which continuously sense an air gap (106) between the rotor (104) and the stator (102), an encoder (210) which continuously detects an angular position of the rotor (104), and a processor (215) which receives data from the sensors (205) and the encoder (210) and determines in real-time an insertion order for inserting the plurality of magnets (110) in a surface of the rotor (102). The control system (200) applies a feedback loop while performing the insertion process to adjust the insertion order based on changes in the data received.