Double-Wound Stator Coil Layout to Reduce Phase Insulation
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Solution Overview
Problem
The need for phase-to-phase insulation increases due to double-wound coils of different phases being located close to each other in the radial direction, leading to higher potential differences and increased costs in stators for rotating electrical machines.
Innovation Solution
A stator design with double-wound coils that are wound concentrically around the stator core, where the slot insertion portions of different phases are inserted into different slots, and crossovers are arranged to avoid radial adjacency, reducing the need for phase-to-phase insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If double-wound coils of different phases are arranged close to each other in the radial direction, then the stator size is reduced, but the need for phase-to-phase insulation measures increases due to higher potential differences
Solution Approach 1:
The patent transitions from radial arrangement to axial arrangement of coil portions. Specifically, the first coil portion and second coil portion of each double-wound coil are positioned at different axial locations, allowing different phase coils to be closely arranged in the radial direction without direct radial contact, thereby reducing insulation requirements while maintaining compact size.
Solution Approach 2:
The patent introduces the stator core as an intermediary structure between coils of different phases. By positioning coils on opposite sides of the stator core and utilizing the core's physical separation, the design achieves close radial arrangement while the stator core acts as a natural insulation barrier, reducing the need for additional phase-to-phase insulation measures.
2Device complexity
If one type of double-wound coil is used for all phases, then the number of coil types is reduced and winding method is simplified, but phase-to-phase insulation measures are required due to potential differences between different phases
Solution Approach 1:
The patent uses axial positioning to differentiate between coil portions of the same phase while maintaining identical coil structures. The first coil portion and second coil portion are positioned at different axial locations, allowing uniform double-wound coils to be used across all phases without requiring additional insulation measures between phases.
Solution Approach 2:
The patent merges the insulation function into the stator core structure itself. By positioning coils of different phases on opposite sides of the stator core, the core serves as both the magnetic circuit and the insulation barrier, eliminating the need for separate phase-to-phase insulation measures while using uniform coil structures.
3Volume of moving object
If double-wound coils are arranged with slot insertion portions radially adjacent, then the stator size is minimized, but phase-to-phase insulation measures are required due to high potential differences at locations farthest from the neutral point
Solution Approach 1:
The patent introduces axial positioning as an additional dimension for arranging coil portions. The first coil portion and second coil portion are positioned at different axial locations, allowing slot insertion portions to be radially adjacent for compact size while preventing direct radial contact between different phase coils, thereby reducing insulation requirements.
Solution Approach 2:
The stator core serves as an intermediary structure between radially adjacent coil portions of different phases. By positioning coils on opposite sides of the stator core with axial separation, the design achieves minimal stator size while the stator core provides natural insulation, reducing manufacturing costs associated with additional insulation measures.
Data Source
AI summary
A stator for a rotating electrical machine includes a stator core and a stator coil of a plurality of phases. The stator coil is formed by winding a plurality of double-wound coils of each phase around the stator core along an entire circumference of the stator core. Each of the plurality of double-wound coils concentrically include a coil portion with a larger circumference length and a coil portion with a shorter circumference length. The double-wound coil of each phase includes a first double-wound coil farthest from a neutral point and a second double-wound coil other than the first double-wound coil. Of the first double-wound coils of first to third phases, only the combination of the first double-wound coils of the first and second phase overlaps in a specific circumferential section corresponding to at least one slot, and the first double-wound coils of different phases are inserted in different slots.