Magnetic Levitation Stator Shielding for Eddy Current Loss Control
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Solution Overview
Problem
Magnetic bearing devices suffer from significant eddy current losses and heat dissipation issues due to the use of electrically conductive materials like aluminum in the stator housing, which are exacerbated by magnetic fields generated during operation.
Innovation Solution
Incorporation of a shielding mechanism within the stator housing that prevents magnetic fields from escaping, allowing the use of conductive materials like aluminum while reducing eddy current losses and ensuring effective heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electrically conductive materials like aluminum are used in the stator housing, then heat dissipation is improved, but eddy current losses increase significantly
Solution Approach 1:
A magnetic shielding layer made of electrically non-conductive material is introduced as an intermediary between the magnetic field source and the aluminum stator housing. This shielding layer blocks magnetic field lines from penetrating into the conductive housing, thereby preventing eddy current formation while allowing the aluminum to continue its heat dissipation function.
Solution Approach 2:
The stator housing is designed with differentiated local properties: the magnetic shielding layer is applied specifically in regions where magnetic field penetration would cause eddy currents, while other regions of the housing maintain full thermal conductivity for heat dissipation. This localized application of shielding material optimizes both thermal management and energy efficiency.
2Loss of energy
If magnetic shielding is added to reduce eddy current losses, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The magnetic shielding is implemented as a thin-walled layer or coating applied to the stator housing rather than a bulky structural component. This thin-film approach provides effective magnetic field blocking while adding minimal structural complexity and maintaining the overall compact design of the device.
Solution Approach 2:
The stator housing is designed as a composite structure combining electrically conductive material (aluminum) for heat dissipation with an electrically non-conductive magnetic shielding layer for field containment. This composite design integrates multiple functions into a unified structure, reducing overall device complexity compared to separate components.
3Loss of energy
If magnetic shielding material is incorporated, then eddy current losses are reduced, but manufacturing cost increases
Solution Approach 1:
The magnetic shielding is applied as a thin coating or lining on the stator housing surface rather than using thick blocks of shielding material. This reduces the quantity of expensive magnetic shielding material required while maintaining effective field containment, thereby lowering manufacturing costs.
Solution Approach 2:
The patent employs cost-effective magnetic shielding materials and application methods that provide sufficient performance for the intended application lifecycle. The shielding layer is designed to be simple and inexpensive to manufacture, potentially using readily available materials and standard coating techniques.
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 shielding effectively reduces eddy current losses and maintains efficient heat dissipation, leading to a more compact and cost-effective magnetic levitation device with improved performance.
Implementation Method 1
the stator (2) comprises a shielding (4) which extends in the circumferential direction along a plurality of coil cores (25), wherein the shielding (4) extends in the axial direction A from a first shielding end (41) to a second shielding end (42)
Implementation Method 2
at least one concentrated winding (61) is arranged at each longitudinal leg (26), which surrounds the respective longitudinal leg (26)
Implementation Method 3
Magnetic bearing devices for contactless magnetic bearing of a rotor have the advantage that they do not require mechanical bearings for the rotor. The rotor is supported or stabilized by magnetic forces
Implementation Method 4
the stator of the magnetic bearing device has an aluminum housing, wherein it is disadvantageous for the magnetic bearing device if the housing is made from an electrically conductive material, since this leads to the generation of eddy currents
Data Source
AI summary
A magnetic levitation device includes a stator including coil cores, each coil core having a longitudinal leg extending from a first end in an axial direction to a second end, and a transverse leg arranged at the second end of the longitudinal leg, and extending in a radial direction. A back iron is arranged at the first end of the coil cords and connects the first ends of the longitudinal legs. A concentrated winding is provided on each longitudinal leg, and surrounds the longitudinal leg. The stator has a cup-shaped recess into which the rotor is capable of being inserted, the cup-shaped recess arranged at an axial end of the stator, and a shielding extending in the circumferential direction along the coil cores. The shielding extends in the axial direction from a first shielding end to a second shielding end.