Multi-Layer Stator Winding for Compact Rotating Electric Machine
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Solution Overview
Problem
The stator in rotating electric machines with distributed-winding stators experiences increased bending radius and bulked-up coil ends due to the increase in the number of turns of the conductor wire in lap-wound coils, leading to a less compact design.
Innovation Solution
A stator design with multiple layers of lap-wound coils, where each coil side is inserted in specific slots along the radial direction, varying the sectional area and number of turns in each layer to minimize bending radius and reduce coil end size, and offsetting phases between layers to reduce torque ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of turns of the conductor wire in lap-wound coils is increased, then the electrical performance is improved, but the bending radius at the crowning portions increases and the coil ends bulk up
Solution Approach 1:
The patent divides the stator winding into multiple independent layers (first layer, second layer, third layer, etc.), with each layer containing a subset of the total coil turns. This segmentation allows each layer to have fewer turns, reducing the bending radius and coil end bulk while maintaining the total electrical performance through the cumulative effect of all layers.
Solution Approach 2:
The patent transitions from a single-layer winding configuration to a multi-layer winding configuration arranged radially. By distributing turns across multiple radial layers instead of concentrating them in one layer, the patent reduces the bending radius at crowning portions and minimizes coil end bulk while preserving the required number of total turns for electrical performance.
2Power
If the number of turns of the conductor wire is increased, then the electrical performance is improved, but the machine becomes less compact
Solution Approach 1:
The stator winding is segmented into multiple layers with different numbers of turns, allowing the machine to achieve high electrical performance without requiring a single large-bending-radius coil. This segmentation enables a more compact overall machine design.
Solution Approach 2:
Different layers are assigned different numbers of turns (e.g., first layer has fewer turns, second layer has more turns), creating local variations in winding density. This local quality approach allows optimization of both compactness and electrical performance in different radial zones of the stator.
3Volume of moving object
If coil sides are arranged in multiple layers, then the bending radius is reduced and coil ends are minimized, but the manufacturing complexity increases
Solution Approach 1:
The winding process is divided into multiple sequential steps, with each layer being wound and inserted independently. This segmentation of the manufacturing process, while adding steps, allows for standardized procedures for each layer and reduces the complexity of handling extremely large-bending-radius coils.
Solution Approach 2:
Each layer of coil windings is prepared and inserted into the stator slots in a predetermined sequence (first layer, then second layer, etc.). This preliminary planning of the winding sequence simplifies the overall manufacturing process by establishing a systematic approach rather than attempting to install all turns simultaneously.
Data Source
AI summary
A stator includes: a stator core with N pieces of slots ranging along an axial direction, which are formed side-by-side along a circumferential direction; and a stator winding installed in the slots at the stator winding. The stator winding includes a plurality of winding groups, each made up with N pieces of lap-wound coils each formed by winding a conductor wire a plurality of times. The winding groups are disposed in a plurality of layers set side-by-side along a radial direction at the stator core. One coil side at each of the lap-wound coils is inserted in a specific slot on an inner side along the radial direction in a specific layer and another coil side of the lap-wound coil is inserted in another slot on an outer side along the radial direction in the specific layer.