Six-Phase Flat Wire Wave Winding Without Loop Currents
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Solution Overview
Problem
The challenge in developing a six-phase flat wire wave winding structure is the difficulty in ensuring consistent spans of U-shaped coils and the increased manufacturing costs and efficiency losses due to unbalanced in-phase branches and loop currents, particularly as the number of phases increases.
Innovation Solution
The implementation of a six-phase flat wire wave winding structure where each phase has conductors in all layers of the same stator slot, with uniform and symmetric distribution, eliminating the need for insulating paper between layers, and using symmetrical three-phase wave windings with a 30-degree electrical angle difference to balance branch potentials and prevent loop currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional flat wire wave winding structure with U-shaped coils is used in a six-phase motor, then the motor can achieve six-phase operation with improved fault tolerance, but the winding process becomes highly difficult and manufacturing costs increase due to inconsistent coil spans and unbalanced in-phase branches
Solution Approach 1:
The six-phase winding is segmented into two independent three-phase windings (first three-phase winding and second three-phase winding), each with its own set of coils. This segmentation allows each three-phase winding to be wound and assembled independently, significantly reducing the complexity of the winding process while maintaining six-phase operation capability and fault tolerance
Solution Approach 2:
The patent combines two three-phase windings into a six-phase motor structure, where the first three-phase winding and second three-phase winding share the same stator slots but are electrically independent. This merging approach enables six-phase operation with improved fault tolerance while using standard three-phase winding techniques that are easier to manufacture
2Adaptability or versatility
If multiple layers of different-phase conductors are placed in the same stator slot, then the motor can achieve higher phase count, but insulating paper must be disposed between layers reducing slot fill factor and increasing costs
Solution Approach 1:
The stator slots are segmented into multiple layers, with each layer containing conductors of the same phase. This layer-based segmentation eliminates the need for insulating paper between different-phase conductors since adjacent layers contain identical phase conductors, thereby maximizing slot fill factor while supporting six-phase operation
Solution Approach 2:
Different layers within the same stator slot are assigned different phase conductors based on their positional requirements, while ensuring that conductors in adjacent layers are of the same phase. This local quality approach optimizes space utilization by eliminating unnecessary insulation between layers
3Adaptability or versatility
If U-shaped coils with inconsistent spans are used, then the motor can accommodate six-phase winding, but manufacturing costs increase and loop currents are generated causing efficiency losses
Solution Approach 1:
The six-phase winding is divided into two independent three-phase windings, each with properly balanced coil spans. This segmentation prevents loop currents by ensuring that each three-phase winding forms closed magnetic circuits with balanced spans, eliminating the energy losses associated with unbalanced in-phase branches
Solution Approach 2:
The patent ensures that corresponding branches in the first and second three-phase windings have equal electrical potentials by designing symmetrical winding configurations with equal spans. This equipotentiality prevents circulating currents between parallel branches, eliminating energy losses while maintaining six-phase operation capability
Data Source
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AI summary
Embodiments of this application provide a six-phase flat wire wave winding structure, a six-phase motor, a powertrain, and a vehicle. Each phase of wave winding has a wire-in end, a wire-out end, and a wire located between the wire-out end and the wire-in end. The six-phase flat wire wave winding structure is applicable to a 2M-layer (M=l, 2, 3...) six-phase motor whose quantity of slots of each phase in each pole is q, whose quantity of stator slots is 6q (q=1, 2, 3...) times of a quantity of poles, and whose quantity a of parallel branches is 1 or 2. Each phase of wave winding has conductors in all layers of a same stator slot, and the wave windings are uniformly and symmetrically distributed. Potentials of branches are balanced, and there is no loop current. Conductors in different layers of a same slot are in-phase, and do not need to be isolated by insulating paper. This helps improve a slot fill factor and reduce costs. In addition, problems that a flat wire winding process is highly difficult and manufacturing costs are high due to an increase in a quantity of phases of the six-phase motor are effectively resolved.