Stator Winding Arrangement for Balanced Slots and Lower Circulating Currents
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Solution Overview
Problem
Conventional electric motor stator winding structures lead to unbalanced winding, resulting in unnecessary circulating currents and insulation damage due to unbalanced wire spans across layers, and existing solutions are either inefficient or costly.
Innovation Solution
A stator assembly with a three-phase electric machine featuring a winding arrangement where conductors form branches that alternately occupy slots in diagonal subsets, with span options of full-pitch, short-pitch, or long-pitch, ensuring balanced and symmetrical winding patterns to eliminate circulating currents and maintain insulation integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conductors are inserted only in certain layers of slots (as in CN207766054), then the winding structure can be simplified, but circulating currents and losses increase due to unbalanced winding
Solution Approach 1:
The patent applies asymmetry by deliberately creating an unbalanced winding structure where different windings occupy different numbers of layers. Specifically, one winding occupies three layers while another occupies two layers in the same slot, which intentionally creates asymmetrical current distribution to eliminate circulating currents and reduce losses.
2Reliability
If two adjacent legs in the winding span more than a layer, then the winding coverage is improved, but wire damage and insulation performance deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the winding into multiple discrete legs, each spanning exactly one layer. This segmentation prevents any single leg from spanning multiple layers, thereby avoiding wire damage and maintaining insulation performance while still achieving adequate winding coverage through the distributed arrangement of multiple segmented legs.
3Loss of energy
If a balanced winding structure is implemented, then circulating currents are eliminated, but the winding structure becomes more complex and costly
Solution Approach 1:
The patent applies merging by combining multiple windings into shared slots where one winding occupies three layers and another occupies two layers. This merging approach achieves balanced winding distribution and eliminates circulating currents while avoiding the complexity of completely separate winding structures, as the windings share the same physical space in a coordinated manner.
Data Source
AI summary
A winding arrangement provided on a stator of an electric machine. The winding arrangement includes at least four windings. A first winding and a second winding occupied a first subset of slots; and a third winding and a fourth winding occupied a second subset of the slots. The first subset and the second subset of the plurality of slots are adjoined to each other. A span between two adjacent slots concerning the first winding, the second winding, the third winding, and the fourth winding is chosen from a full-pitch, a short-pitch, and a long-pitch to result in the winding arrangement where the first subsets in a first half of the slots is diagonal to the second subset in a second half of the slots, and the second subset in the first half of the slots is diagonal to the first subset in the second half of the slots.