Linear Motor Stator Magnet Arrangement for Thrust Optimization
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Solution Overview
Problem
Existing linear motors face inefficiencies due to high magnet usage costs, reduced thrust, and increased weight, along with difficulties in magnetization and core loss, particularly when using ferrite magnets, which affect compressor performance.
Innovation Solution
A linear motor design where multiple magnets are fixed to the stator in the same direction, reducing centering force and increasing thrust, using a mover core made of magnetic material instead of permanent magnets, and incorporating grain-oriented electrical steel to minimize core loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ferrite magnets are used instead of Nd magnets, then manufacturing cost is reduced, but mover weight increases due to larger magnet quantity required
Solution Approach 1:
The patent inverts the conventional arrangement by coupling magnets to the stator instead of the mover. This allows the use of cheaper ferrite magnets while keeping the mover lightweight, as the magnets are now part of the stationary stator assembly rather than the moving component.
2Stability of the object's composition
If multiple magnets are magnetized in different directions, then centering force increases, but thrust in top dead center or bottom dead center direction is weakened
Solution Approach 1:
The patent applies different magnetization directions to different regions of the stator magnets. Specifically, magnets at opposite positions are magnetized in opposite directions to generate centering force, while magnets at adjacent positions are magnetized in the same direction to generate thrust, thereby achieving both centering and thrust requirements simultaneously.
3Device complexity
If one air gap is formed eccentrically, then motor structure is simplified, but alpha waveform becomes asymmetrical and control characteristics deteriorate
Solution Approach 1:
The patent intentionally creates asymmetry in the magnetic circuit by forming one air gap eccentrically relative to the magnetic path center. This asymmetric design simplifies the motor structure while the control system compensates for the waveform asymmetry through appropriate current control strategies.
4Use of energy by moving object
If magnets are mounted on the inner circumferential surface of the core, then magnetic circuit efficiency is improved, but magnetization operation becomes difficult
Solution Approach 1:
The patent inverts the conventional mounting location by placing magnets on the outer circumferential surface of the stator core instead of the inner surface. This makes magnetization operation much easier while still maintaining efficient magnetic circuit performance through proper magnetic flux path design.
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 enhances motor efficiency, reduces magnet usage, and improves control characteristics while lowering costs and weight, achieving higher thrust and longer effective stroke ranges.
Implementation Method 1
a winding coil provided on the stator and configured to generate a magnetic flux
Implementation Method 2
the mover reciprocates by the magnetic flux formed in the core
Implementation Method 3
a magnet forming a magnetic circuit with the core and the winding coil
Data Source
AI summary
In a linear motor and the linear compressor having the same according to the present disclosure, a plurality of magnets are coupled to a stator equipped with a winding coil, and a mover core made of magnetic material instead of a permanent magnet is provided on the mover, and by the magnetizing plurality of magnets in the same direction, the motor output can increase by increasing thrust instead of decreasing the centering force for the mover core. In addition, as it is applied to a two-pore motor, it is possible to easily control the mover core and to easily perform an assembly operation and a magnetization operation for the magnet. In addition, as the stator is made of a grain-oriented core, core loss may be reduced and the motor efficiency may be improved.