Laminated Core Joining Layout for Lower Eddy Current Loss
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Solution Overview
Problem
Existing laminated cores for electromagnetic machines suffer from high eddy current losses and limited fill factor due to restrictive production methods, which hinder the achievement of high power density and efficiency.
Innovation Solution
A laminated core is created using a plurality of soft magnetic alloy sheets joined by filler-free, substance-to-substance joints formed through laser spot welding, allowing for optimized distribution and size of joints to minimize adverse effects on electromagnetic properties and enhance joint strength, enabling the production of very thin layers with lower eddy current losses and higher efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional production methods are used to join lamination sheets, then manufacturing simplicity is maintained, but eddy current losses increase and efficiency decreases
Solution Approach 1:
The patent divides the joining process into multiple small filler-free joints distributed across the lamination sheets rather than using traditional continuous adhesive layers. This segmentation reduces the insulating material volume and minimizes eddy current paths, directly addressing the energy loss problem while maintaining manufacturability through automated joining processes
Solution Approach 2:
The patent changes the joining parameters by using filler-free substance-to-substance joints instead of adhesive-based connections. This parameter change eliminates the need for insulating adhesive layers, reduces joint volume, and creates optimal electrical insulation properties that minimize eddy current losses while improving overall efficiency
2Quantity of substance
If adhesive layers are used to join lamination sheets, then ease of manufacture is improved, but fill factor decreases due to increased insulating material volume
Solution Approach 1:
The patent extracts and removes the adhesive layers from the lamination sheet joining process, replacing them with direct substance-to-substance joints. This extraction eliminates the volume occupied by insulating adhesive material, directly increasing the fill factor and the amount of magnetically conductive material in the core while maintaining manufacturing simplicity through automated joining processes
Solution Approach 2:
The patent discards the traditional adhesive joining method in favor of filler-free substance-to-substance joints. By eliminating the adhesive layer, the volume that would have been occupied by non-magnetic material is now available for magnetic material, thereby recovering and maximizing the fill factor and magnetic material quantity in the core
3Strength
If fewer and larger joints are used to join lamination sheets, then joint strength is improved, but electromagnetic properties deteriorate due to increased adverse effects
Solution Approach 1:
The patent segments the joining locations into multiple small filler-free joints distributed across the lamination sheets. This segmentation distributes the mechanical load across numerous connection points, maintaining adequate joint strength while minimizing the total volume of joints that could adversely affect electromagnetic properties, thus resolving the contradiction between strength and electromagnetic performance
Solution Approach 2:
The patent applies local quality by creating small, localized filler-free joints at specific distributed positions rather than using large continuous joints. Each small joint provides localized bonding strength while the distributed arrangement ensures that no single large joint disrupts the electromagnetic field, thereby maintaining both mechanical strength and electromagnetic properties
4Loss of energy
If thicker lamination sheets are used, then manufacturing simplicity is maintained, but eddy current losses increase
Solution Approach 1:
The patent changes the lamination sheet thickness parameter to very thin sheets, which directly reduces eddy current losses since eddy current losses are proportional to the square of the sheet thickness. The use of filler-free substance-to-substance joining methods enables this parameter change by providing adequate bonding and electrical insulation without requiring thick sheets, thus reducing energy losses while managing device complexity
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 method allows for the mass production of high-performance laminated cores with reduced eddy current losses and improved efficiency, suitable for medium-sized and large series production, while maintaining high productivity and flexibility in dimensions and materials.
Implementation Method 1
the joints may, for example, be formed of resolidified molten material of the lamination sheets and be formed by a process such as welding, e.g. spot welding or laser spot welding
Implementation Method 2
The sheet material is fused by a laser beam from the exposed main surface of the top-most lamination sheet in the stack to a defined depth and thus over a defined number of layers
Implementation Method 3
The solidification of the molten material produces a substance-to-substance joint between the layers
Implementation Method 4
the rotor and the stator have a plurality of identical individual sheets referred to as 'laminations' or 'layers' that are stacked one on top of another and electrically insulated from one another
Data Source
AI summary
A laminated core comprising a plurality of lamination sheets made of a soft magnetic alloy is provided. The lamination sheets have a main surface and a thickness d. The main surfaces of the lamination sheets are stacked one on top of another in a direction of stacking. Adjacent lamination sheets are joined to one another by a plurality of substance-to-substance joints, the joints being filler-free and entirely surrounded by the main surfaces of the adjacent lamination sheets.