Compact Multiphase Wave Winding for High Specific Torque
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Solution Overview
Problem
Existing electric machine windings face challenges in achieving high torque, energy efficiency, and compact design, with issues such as space inefficiency, mechanical properties, and high production costs, particularly when the value of K (the ratio of active to passive winding sections) is high, and there is a lack of optimal solutions for inserting conductors into slots without damage.
Innovation Solution
A compact multiphase wave winding design with radial orientation and pseudo-helical, helical, and deformed topologies, where conductors are shaped into straight segments and winding overhangs with specific deformations to fit tightly within the stator slots, allowing for efficient magnetic flux transfer and reduced material usage, enabling high specific torque and low mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large number of discrete coils are used to achieve high torque and high K values, then the magnetic performance is improved, but the device complexity and production time increase significantly
Solution Approach 1:
Multiple discrete coils of the same phase are merged into a single continuous block coil structure. The patent describes 'a first block coil comprising a first continuous conductor forming a first plurality of coils of a first phase' and 'a second block coil comprising a second continuous conductor forming a second plurality of coils of a second phase'. This merging reduces the number of separate components while maintaining the torque-generating capability through the continuous conductor design.
Solution Approach 2:
The continuous conductor is segmented into multiple coil sections within each block coil, where each section corresponds to a specific stator tooth. The patent mentions 'a first number of turns around a first stator tooth and a second number of turns around a second stator tooth'. This segmentation allows optimization of turns distribution across different teeth while maintaining the benefits of a continuous conductor structure.
2Power
If conventional wave winding is used with high K values, then the active section is maximized, but the winding overhangs require excessive space and cannot be properly routed
Solution Approach 1:
The winding overhangs are routed not only in the radial direction but also in the axial direction, utilizing the third dimension. The patent describes that conductors 'extend from the slots in a radial direction away from the stator core to a position radially outside the stator core'. This spatial reconfiguration allows the overhangs to bypass each other in the axial dimension, reducing the radial space requirement and enabling proper routing even with high K values.
3Ease of manufacture
If conductors are inserted into slots without proper shaping, then the assembly is simplified, but the conductors cannot be properly positioned and may be damaged
Solution Approach 1:
The conductors are pre-shaped outside the stator core before insertion, with the winding overhangs formed into their final configuration. The patent states that conductors 'extend from the slots in a radial direction away from the stator core to a position radially outside the stator core' and that the block coils are formed with specific turn distributions. This preliminary shaping ensures that when the conductors are inserted into the slots, they are already in the correct position and orientation, eliminating the need for complex in-situ manipulation and preventing damage during assembly.
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
The design achieves high specific torque, low energy losses, and efficient thermal and electrical performance while minimizing material usage and production complexity, making it suitable for direct drive applications like electric vehicles.
Implementation Method 1
The straight segments of the conductors are inserted into the slots of the stator ferromagnetic core. The straight segments are connected by winding overhangs... allowing for efficient magnetic flux transfer
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The invention is the compact multiphase wave winding of a high specific torque electric machine The invention is the compact multiphase wave winding (6) of the electric machine. Winding (6) is filling the slots (5) of the stator ferromagnetic core (3) and comprise one or multiple layers (40). Winding (6) fills the slots (5). Winding comprise N or a multiple on N conductors (8), where N represents the number of winding phases. Conductor (8) comprises or is assembled by parallel straight segments (10) and winding overhangs (11). Between the two straight segments (10) of one conductor (8) there are N teeth (4) and N-1 slots (5) or N+1 teeth (4) and N slots (5). Straight segments are connected by winding overhangs which shape in tangential axial plane differs for less than one sixth of magnetic period (7) from ellipse shape with one axis equal to half of magnetic period (7) and other axis length between half and three quarters of magnetic period (7) length.