Hairpin Motor Winding Layout for Balanced Parallel Current
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Solution Overview
Problem
Existing electric motor designs with multi-layer flat copper wire wave windings experience uneven electromagnetic coupling between parallel-wound branches of the same phase, leading to unbalanced current flows and increased copper loss.
Innovation Solution
The winding structure is designed with parallel-wound sub-windings of each phase located in non-adjacent layers of the stator slots, balanced by counter-electromotive forces, and optimized with hairpin-type conductors to minimize conductor connection sections and enhance heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multi-layer flat copper wire wave windings are wound in parallel with one phase and multiple phase branches, then skin effect loss is reduced, but electromagnetic coupling between parallel winding branches becomes uneven
Solution Approach 1:
The patent applies asymmetry by intentionally designing different winding pitches for different layers of conductors. Specifically, odd layers use one winding pitch while even layers use a different winding pitch, creating asymmetric electromagnetic coupling characteristics that balance the overall current distribution across parallel branches and reduce electromagnetic coupling unevenness.
Solution Approach 2:
The patent changes the winding pitch parameter differently for different layers. By setting odd layers with winding pitch y1 and even layers with winding pitch y2, the patent modifies the electromagnetic coupling parameters to achieve balanced current flows while maintaining the multi-layer flat copper wire structure that reduces skin effect loss.
2Ease of manufacture
If conductors are connected head-to-head and tail-to-tail to form neutral points, then phase out connection is achieved, but current loops are generated causing additional electrical losses
Solution Approach 1:
The patent extracts or eliminates the harmful current loops by changing the connection topology. Instead of connecting conductors head-to-head and tail-to-tail which creates closed current loops, the patent uses different winding pitches for odd and even layers that prevent loop formation, thereby removing the source of additional electrical losses while maintaining manufacturing feasibility.
3Device complexity
If parallel-wound branches are connected to form neutral points, then three-phase winding is completed, but unbalanced current flows increase copper loss
Solution Approach 1:
The patent uses asymmetric winding pitch design where odd layers have pitch y1 and even layers have pitch y2. This asymmetry creates different electromagnetic coupling strengths for different parallel branches, which balances the current distribution and reduces overall copper loss while completing the three-phase winding structure.
Solution Approach 2:
By changing the winding pitch parameter across different layers (y1 for odd layers, y2 for even layers), the patent optimizes the electromagnetic coupling characteristics to achieve balanced current flows in parallel branches, thereby reducing copper loss without significantly increasing device complexity.
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 balances counter-electromotive forces, prevents current loops, reduces electrical losses, and improves power density and heat dissipation, aligning with the trend of miniaturization and facilitating easier assembly.
Implementation Method 1
balances the counter-electromotive forces induced by the parallel-wound sub-windings of each phase of winding structure of stator under load operation
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a
AI summary
Disclosed are a winding structure for an electric motor and an electric motor. The electric motor comprises an iron core (1) and a multi-phase winding structure (2), wherein the iron core (1) is provided with a plurality of grooves (11) arranged in the circumferential direction, and one side of the iron core (1) is an inserting side, and the other side is a welding side; the multi-phase winding structure (2) is arranged in the plurality of grooves (11) of the iron core (1), each phase of the winding structure (2) comprises N parallel winding sub-windings formed by a plurality of hairpin conductors of different shapes, and N is a positive even number; and the conductors, forming each phase of the winding structure (2), of the same sub-winding are located on a non-adjacent conductor layer corresponding to the grooves (11).