Structured Soft Magnetic Material With Insulated Droplet Boundaries
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Solution Overview
Problem
The fabrication of laminated stator cores for electric machines is complex, labor-intensive, and costly, leading to sub-optimal designs with restricted magnetic circuit configurations and limited cogging reduction, especially in vibration-sensitive applications, due to the constraints of traditional steel laminations and the difficulty in incorporating cooling for increased current density and torque output.
Innovation Solution
A system and method for creating a material with domains having insulated boundaries using a droplet spray subsystem to form molten alloy droplets and a gas subsystem to introduce reactive gases, forming an insulation layer on the droplets, which are then deposited to form a material with insulated boundaries, allowing for improved magnetic properties and reduced eddy current losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional laminated stator cores are constructed by stacking individually laminated thin sheet-metal elements, then eddy current losses are reduced through insulation layers, but the fabrication process becomes complicated, labor-intensive, and costly
Solution Approach 1:
The patent merges multiple separate operations (cutting, coating with insulating layer, assembly) into a single integrated process. Molten metal is sprayed through a substrate and an insulating layer is formed simultaneously during deposition, eliminating the need for separate coating and assembly steps while maintaining eddy current reduction benefits
Solution Approach 2:
The insulating layer is formed preliminarily during the droplet deposition process itself, before final assembly is needed. The insulation coating is applied to droplets as they are being deposited onto the substrate, preparing the structure in advance and eliminating subsequent coating operations
2Reliability
If traditional steel laminations are used with constrained geometry, then magnetic flux alignment is maintained, but magnetic circuit configurations are restricted and cogging reduction is limited
Solution Approach 1:
The invention enables dynamic and complex magnetic circuit configurations by allowing the stator core geometry to be freely designed without being constrained by lamination stacking directions. The sprayed droplet structure can accommodate varying magnetic flux paths and complex geometries while maintaining proper magnetic flux alignment through the flexible net-shape fabrication capability
3Loss of energy
If laminated stator cores are constructed with insulation layers between elements, then eddy current losses are minimized, but cooling incorporation becomes difficult and current density is limited
Solution Approach 1:
The sprayed droplet structure creates a porous or cellular internal architecture within the stator core that allows cooling channels to be easily incorporated. The net-shape fabrication process can directly form cooling passages during deposition, enabling efficient heat removal and allowing higher current densities while the insulating layer between droplets maintains eddy current reduction
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 approach results in a material with enhanced magnetic permeability, low coercivity, and high saturation induction, minimizing eddy current losses and enabling more efficient and cost-effective production of electric machine stator cores with improved performance and design flexibility.
Implementation Method 1
heating the metal material to a softened state
Implementation Method 2
introducing one or more reactive gases proximate in-flight droplets such that the one or more reactive gases creates an insulation layer on the droplets in flight
Implementation Method 3
the droplets form a material having domains with insulated boundaries
Data Source
Figure 1~2
Figure 3~4
Figure 5A~6
AI summary
A system for forming a soft magnetic bulk material of a predetermined shape from a magnetic material and a source of insulating material, including a heating device; a deposition device; a support, and a mask configured as a negative of at least a portion of the predetermined shape. The heating device heats the magnetic material to form particles having a softened state and wherein the deposition device deposits successive layers of particles of the magnetic material in the softened state on the support with the mask located between the deposition device and the support. The mask is indexed to a position relative to the support upon deposition of the successive layers. The mask selectively blocks the successive layers of particles of the magnetic material in the softened state from being deposited on the support forming the soft magnetic bulk material of a predetermined shape on the support.