Plug-In Winding Conductors with Shaping Insulation for High Fill Factor
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Solution Overview
Problem
Existing coil winding processes for electric machines, particularly in vehicle propulsion systems, are limited by the need for bending operations that restrict material choice and hinder efficient power density and weight reduction.
Innovation Solution
The use of flexible, electrically conductive fibers enclosed in a tubular insulating sheath, such as carbon nanotubes or graphene, allows for a plug-in winding design where the sheath determines the conductor's shape, enabling high fill factor and reduced weight through materials like polyetheretherketone (PEEK) that maintain rigidity without deformation, and a method involving heating to set the shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional air-core coils are used in MRI magnets, then the magnet structure is simpler, but the homogeneity of the magnetic field is insufficient and eddy currents are generated
Solution Approach 1:
The patent uses flexible printed circuit boards (FPCs) as thin film structures to create solid-state coils that eliminate eddy currents while maintaining magnetic field homogeneity. The FPCs are laminated onto curved surfaces to form the coil windings, providing both structural integrity and electrical functionality without the problems of conventional air-core coils
Solution Approach 2:
The patent employs composite construction by laminating multiple FPC layers with different conductor trace patterns onto the same curved surface. This composite approach allows the different layers to work together to generate the desired magnetic field while canceling out eddy current effects, achieving both homogeneity and structural stability
2Reliability
If FPCs are laminated onto a curved surface, then eddy currents are eliminated and magnetic field homogeneity is improved, but manufacturing complexity increases
Solution Approach 1:
The conductor traces are pre-designed and pre-laminated onto the FPCs before assembly into the final magnet structure. This preliminary action allows for controlled manufacturing of the FPC components independently, which can then be assembled into the curved configuration, reducing the overall manufacturing complexity
Solution Approach 2:
The FPC technology serves multiple functions simultaneously: it provides the electrical conductor pathways, acts as the structural substrate, eliminates eddy currents through its solid-state construction, and can be laminated onto curved surfaces. This multi-functionality reduces the need for separate components and simplifies the overall manufacturing process
3Device complexity
If multiple FPCs are laminated onto the same curved surface, then coil complexity is reduced and assembly is simplified, but the FPCs must remain flexible during forming
Solution Approach 1:
The FPCs are designed with inherent flexibility allowing them to be laminated onto curved surfaces during the manufacturing process. Once assembled and potentially secured, the flexible FPCs maintain their electrical functionality while conforming to the required geometric shape, reducing coil structure complexity
Solution Approach 2:
The patent uses the curved surface geometry as a template or mold to guide the lamination of FPCs. By copying the surface geometry onto which the FPCs are laminated, the flexible circuits can be formed into the required shapes without complex additional forming operations, maintaining flexibility while achieving the desired coil structure
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 power density and reduces weight by allowing high fill factor and lower material usage, while simplifying assembly and reducing manufacturing costs.
Implementation Method 1
a magnetic resonance imaging (MRI) magnet utilizes a magnet structure including a plurality of flexible printed circuit boards (FPCs) having a plurality of conductor traces formed thereon
Data Source
Figure 1~2
Figure 3
Figure 4~4A
AI summary
The present invention relates to an electric machine (1) having a rotor (3) and a stator (2), wherein the stator (2) and/or the rotor (3) has an electrical plug-in winding (4), which comprises a plurality of rigid insulated electrical conductor elements (5); the conductor elements (5) are arranged in grooves of the stator or of the rotor and their conductor ends (17) project out of the grooves; the conductor ends of the conductor elements (5) are each connected to conductor ends of other conductor elements (5) in order to form the electrical plug-in winding (4); the conductor elements (5) have an electrically insulating insulation sheath (9); characterized in that each conductor element (5) has a multiplicity of flexible fibres (8), in particular of a conductor strand of flexible fibres (8), made of carbon nanotubes or graphene and in that the insulation sheath (9) surrounds the multiplicity of fibres (8) like a hose and is designed in such a way that it gives the electrical conductor element (5) a rigid form.