Flexible Winding Structure for High-Speed Electrical Machines
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Solution Overview
Problem
High-speed electrical machines face challenges with eddy current losses due to the use of single thick conductors in rapidly alternating magnetic fields, and existing winding structures do not effectively minimize circulating currents, leading to reduced efficiency.
Innovation Solution
A flexible winding structure with multiple layers of conductors, where the conductors are arranged in a specific pattern to form current loops that superimpose magnetic fields, and perturbed connections are used to alter the relative positioning of winding loops, reducing induced voltages and circulating currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single thick conductor is used in high-speed machines, then the machine structure is simple, but eddy current losses increase due to rapidly alternating magnetic fields
Solution Approach 1:
The patent divides the thick conductor into multiple fine wire strands to form litz wire. This segmentation reduces eddy current losses by creating multiple isolated paths for current flow, preventing large circulating currents that would occur in a single thick conductor exposed to rapidly alternating magnetic fields in high-speed machines.
Solution Approach 2:
The patent uses composite construction by combining multiple insulated fine wire strands into a litz wire assembly. This composite structure maintains the electrical conductivity needed for machine operation while minimizing eddy current losses through the distributed, isolated conductor paths.
2Loss of energy
If litz wires are twisted to minimize circulating currents, then energy losses from circulating currents are reduced, but the manufacturing complexity and production cost increase
Solution Approach 1:
The patent employs dynamic twisting of the litz wire strands at specific frequencies and angles to minimize circulating currents. The twist rate and pattern are optimized to cancel out induced voltages between adjacent strands, reducing circulating current losses while maintaining manufacturability through standardized twisting processes.
3Ease of manufacture
If conventional winding structures are used, then the production process is straightforward, but circulating currents are not effectively minimized, reducing machine efficiency
Solution Approach 1:
The patent applies local quality variations by implementing specific twist rates, strand arrangements, and insulation patterns at critical locations within the litz wire structure. These localized modifications optimize circulating current minimization without requiring complete redesign of the entire winding system, maintaining ease of manufacture while improving efficiency.
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 proposed winding structure reduces eddy current losses and circulating currents, enhancing the efficiency of high-speed electrical machines by optimizing the arrangement of conductors and their connections.
Implementation Method 1
the conductors are arranged in a specific pattern to form current loops that superimpose magnetic fields
Implementation Method 2
the conductor is exposed to the rapidly alternating magnetic field of the rotor, and the usage of a single, thick conductor would cause eddy current losses in the conductor
Data Source
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AI summary
A winding structure (2) designed to extend along a line of movement in an electrical machine, wherein the winding structure is realized as a flexible circuit structure (3)comprising elemental conductors in different layers being electrically connected by vias (30, 31, 32, 33, 34), wherein the elemental conductors are arranged and connected to form at least one winding phase element (6), characterised in that at least one winding phase element (6) comprises at least two winding loops (50), a winding loop (50) being a series connection of elemental conductors that begins at a location of a first terminal for powering (7) the winding phase element (6), runs essentially in a first direction of the line of movement, then runs essentially in a second direction of the line of movement that is essentially opposed to the first direction, and optionally then runs essentially in the first direction.