Rotor Lamination Local Alloy Tuning to Reduce Flux Leakage
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Solution Overview
Problem
Current electric machine designs for electrified vehicles face challenges in achieving high power outputs and efficiency due to magnetic flux leakage and conflicting property requirements for different regions within the rotor lamination, leading to trade-offs between mechanical strength and electromagnetic performance.
Innovation Solution
The method involves fabricating rotor laminations using additive manufacturing techniques, where different powdered metals with varying compositions are used in specific regions to optimize magnetic permeability, mechanical strength, and core loss, allowing for locally-tuned properties within the lamination plane, such as using FeSi alloys for high permeability regions and non-ferromagnetic austenite stainless steel for reduced permeability in bridge areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform metal alloy is used throughout the rotor lamination, then manufacturing is simple, but magnetic flux leakage occurs and electromagnetic performance is compromised
Solution Approach 1:
The rotor lamination is divided into multiple regions with different metal alloy compositions. High permeability alloy (e.g., FeSi) is used in magnet pocket regions to enhance magnetic flux density, while low permeability alloy is used in bridge regions to reduce magnetic flux leakage. This local differentiation of material properties optimizes electromagnetic performance without compromising manufacturing feasibility through additive manufacturing processes.
2Loss of energy
If high permeability metal alloy is used in bridge regions, then magnetic flux density is improved, but mechanical strength is reduced
Solution Approach 1:
Different metal alloy compositions are strategically assigned to different functional regions of the rotor lamination. The bridge regions, which require high mechanical strength to withstand centrifugal forces, are made from low permeability alloy with superior mechanical properties. The magnet pocket regions, which require high magnetic permeability for optimal electromagnetic performance, are made from high permeability alloy. This spatial differentiation resolves the contradiction between magnetic performance and mechanical strength.
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 enhances torque density and motor efficiency by strategically modifying physical properties, reducing magnetic flux leakage and increasing mechanical strength, thereby improving the overall performance of electric machines in electrified vehicles.
Implementation Method 1
with a laser, fabricating a first region of a rotor lamination layer with a first powdered metal having a first composition
Implementation Method 2
fabricating a first region of a rotor lamination layer with a first powdered metal having a first composition
Implementation Method 3
permanent magnets disposed in the magnet pockets
Data Source
AI summary
An electric machine includes a stack of interlocked rotor core laminations, individual rotor core laminations of the interlocked rotor core laminations including a mortise extending therein and an integrally-formed tenon extending therefrom, wherein the tenons interface with the mortises to interlock adjacent rotor core laminations.