Stator Wire Cross-Section Gradient for AC Loss Reduction
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Solution Overview
Problem
In electrical motors, conventional stator designs face challenges in managing AC loss and space factor due to the skin and proximity effects, particularly when using copper wires with varying cross-sectional areas to balance current carrying capacity and loss minimization.
Innovation Solution
The stator design features a gradient in wire cross-sectional areas across winding layers, with the innermost layer having a smaller cross-sectional area than the outermost, and strategic insulation and parallel/series connections to minimize AC loss while maintaining a high space factor and reducing overall losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single copper wire with larger cross-sectional area is used, then the space factor is high, but the AC loss rapidly increases due to skin effect and proximity effect
Solution Approach 1:
The patent divides the single large cross-sectional area wire into multiple smaller cross-sectional area wires arranged in parallel. This segmentation reduces the AC loss by minimizing the skin effect and proximity effect while maintaining the same total cross-sectional area and space factor through the coordinated arrangement of multiple wires.
Solution Approach 2:
The patent applies different wire cross-sectional areas to different positions within the accommodating trough. Wires at different radial positions have different cross-sectional areas optimized for their local electromagnetic conditions, with the innermost layer having smaller cross-sectional area to reduce proximity effect losses.
2Loss of energy
If multiple copper wires with smaller cross-sectional areas are used, then the AC loss decreases, but the space factor drops and DC resistance increases
Solution Approach 1:
The patent systematically varies the wire cross-sectional area parameter across different layers and positions within the accommodating trough. By optimizing the cross-sectional area of wires at different radial positions, the patent achieves a balance between reducing AC loss through smaller wires and maintaining adequate current carrying capacity and acceptable DC resistance through larger wires where needed.
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 design effectively reduces AC loss and maintains a high space factor, minimizing the impact of the proximity effect and overall losses in the stator, even with smaller copper wire cross-sectional areas.
Implementation Method 1
the AC loss of the copper wire will rapidly increase with the increase of the rotating speed of the motor due to the skin effect and the proximity effect
Data Source
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AI summary
A stator is applied in an electrical motor. The stator includes a hollow iron core and a plurality of coil windings. The hollow iron core has two opposite surfaces and a plurality of accommodating spaces communicated with the surfaces. The accommodating spaces are arranged in an annular pattern. Each of the coil windings includes a plurality of wires winded via the accommodating spaces. Portions of the wires of the coil windings located in the accommodating spaces are radially concentrically arranged to form a plurality of winding layers. In at least one of the accommodating spaces, a wire cross-sectional area of the wire of the innermost one of the winding layers is smaller than a wire cross-sectional area of the wire of the outermost one of the winding layers.