Transverse-Flux Linear Compressor Motor With Virtual Pole Stability

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Solution Overview

Problem

Conventional transverse magnetic flux type reciprocating motors in linear compressors have limitations in reducing height, mechanical stress, vibration distance, friction loss, and require a large number of coils, leading to increased height and mechanical resonance spring issues.

Innovation Solution

A linear compressor design with a transverse magnetic flux type reciprocating motor that reduces the outer diameter by stacking core plates in the axial direction, uses coils with opposite magnetic flux directions, and incorporates a magnet and virtual pole configuration to improve magnetic interaction stability and reduce mechanical stress and friction loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a transverse magnetic flux type reciprocating motor is used to produce the same output as a longitudinal linear motor, then the motor can be designed with a different flux direction, but the outer diameter of the motor increases, leading to increased height of the linear compressor

Engineering Contradiction:
ImproveoutputVSAvoidheight
Core Design Contradiction:
PowerVSLength of stationary object

Solution Approach 1:

The patent transitions from a longitudinal magnetic flux type motor to a transverse magnetic flux type motor, changing the dimension of magnetic flux direction from axial to radial. This dimensional change allows the motor to generate the same output with a reduced outer diameter, thereby reducing the overall height of the linear compressor while maintaining power output.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent modifies key parameters of the motor design by changing the magnetic flux direction from longitudinal to transverse, and by optimizing the arrangement of magnets and coils. These parameter changes enable the motor to achieve the same output with a more compact structure, reducing the height of the linear compressor.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a mechanical resonance spring is installed in the transverse magnetic flux type reciprocating motor, then the motor can provide mechanical resonance for compression, but the mechanical stress limit and vibration distance are limited

Engineering Contradiction:
Improvecompression efficiencyVSAvoidmechanical stress limit
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent replaces the mechanical resonance spring system with an electromagnetic resonance system. Instead of using a mechanical spring to provide resonance, the patent uses the interaction between the transverse magnetic flux and the reciprocating motion to generate compression, eliminating the mechanical stress limitations and vibration distance constraints of a physical spring.

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

3Productivity

If a mechanical resonance spring is used for compression, then the compression function is provided, but the mover becomes eccentric due to lateral force, causing friction loss with the stator

Engineering Contradiction:
Improvecompression functionVSAvoidfriction loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent eliminates the mechanical resonance spring and its associated lateral forces by using a transverse magnetic flux system. The electromagnetic interaction provides the compression function without creating eccentricity or lateral forces that would cause friction between the mover and stator, thereby reducing energy loss.

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

4Power

If conventional transverse magnetic flux type reciprocating motor design is used, then the motor structure is established, but a larger amount of coils is required compared to longitudinal linear motor, increasing device complexity

Engineering Contradiction:
ImproveoutputVSAvoidcoil quantity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent optimizes the parameters of the transverse magnetic flux system by changing the magnetic flux direction and optimizing the arrangement of magnets and coils. These parameter changes allow the motor to generate the same output with fewer coils compared to conventional designs, reducing device complexity while maintaining power output.

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 design achieves a reduced height, improved magnetic interaction efficiency, and stability of the axial reciprocating motion, while minimizing operator errors and assembly costs, and prevents interference between the cylinder and electromagnetic interaction.

Implementation Method 1

an inner stator coupled to an outer circumferential surface of the piston, and reciprocating in an axial direction by electromagnetic interaction with the coil

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 2

a magnet disposed on the teeth shoe and facing the inner stator, and a virtual pole disposed on the teeth shoe, disposed in front of or behind the magnet along the axial direction, and facing the inner stator

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Data Source

PatentEP4001647B1Linear compressor
Publication Date: 2024.05.15 LG ELECTRONICS INC
  • EP4001647B1 patent drawingFigure 1
  • EP4001647B1 patent drawingFigure 2
  • EP4001647B1 patent drawingFigure 3

AI summary

A linear compressor is disclosed. The linear compressor according to the present disclosure comprises a frame; an outer stator including a stator core disposed on the frame, a teeth portion extending inward from the stator core, and a teeth shoe extending in a circumferential direction from an inner end of the teeth portion; a coil disposed on the teeth portion; a cylinder disposed on the frame; a piston disposed in the cylinder; an inner stator coupled to an outer circumferential surface of the piston, and reciprocating in an axial direction by electromagnetic interaction with the coil; a magnet disposed on the teeth shoe and facing the inner stator; and a virtual pole disposed on the teeth shoe, disposed in front or behind in an axial direction of the magnet, and facing the inner stator, wherein the outer stator comprises a plurality of core plates stacked in the axial direction.