Slotless Stator Winding Layout for Lower Eddy Current Loss
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Solution Overview
Problem
Existing stators for electric machines face inefficiencies due to circulating voltage and eddy current losses, which are not adequately addressed by current designs, particularly in small but powerful motors used in mobile applications.
Innovation Solution
A stator design featuring a slotless phase winding with conductive elements arranged in a serpentine structure, including active and inactive segments, where the conductive elements are twisted in the inactive regions to vary the distance from the rotor magnets, reducing overall voltage integral and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional stator windings are used, then the structure is simple, but circulating voltage and eddy current losses increase
Solution Approach 1:
The winding is divided into multiple conductive elements, each independently insulated and arranged in a serpentine pattern. This segmentation allows each element to be optimized for reduced eddy current paths while maintaining overall winding functionality, directly addressing the energy loss problem without excessive complexity.
Solution Approach 2:
The conductive elements are arranged in a serpentine (curved) structure rather than straight lines, and twisted in inactive regions. This curved geometry reduces the voltage integral across the winding and minimizes circulating voltage effects, solving the energy loss issue while the regular serpentine pattern keeps manufacturing manageable.
2Loss of energy
If conductive elements are arranged in a straight pattern, then manufacturing is easier, but voltage integral and eddy current losses increase
Solution Approach 1:
The serpentine arrangement of conductive elements creates curved paths that reduce the voltage integral and eddy current loops. While more complex than straight lines, the regular repeating pattern of the serpentine design allows for standardized manufacturing processes and tooling.
Solution Approach 2:
The conductive elements are twisted in inactive regions to change their spatial orientation and distance from magnets. This parameter change optimizes the magnetic coupling and reduces eddy current losses, while the twist can be incorporated into the winding process through controlled deformation during manufacturing.
3Stability of the object's composition
If uniform distance from magnets is maintained, then winding arrangement is simple, but magnetic field distribution becomes non-uniform
Solution Approach 1:
Different sections of the conductive elements are positioned at different distances from the magnets - active regions are optimized for magnetic coupling while inactive regions are twisted to achieve specific spacing. This local optimization creates more uniform overall magnetic field distribution while the patterned approach keeps manufacturing feasible.
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 proposed stator design reduces circulating voltage and eddy current losses, leading to increased efficiency and a more uniform magnetic field distribution, thereby improving the performance of electric machines in mobile applications.
Implementation Method 1
By applying current through the windings of the stator, the resulting magnetic field interacts with the magnets of the rotor to drive rotation of the rotor and shaft
Implementation Method 2
The insulating housing for each of the conductive elements may reduce eddy current losses associated with its respective conductor during operation of the stator
Data Source
AI summary
A stator for interacting with magnets carried by a rotor of an electric machine, the stator comprising: an active region arranged to be aligned with the magnets carried by the rotor; a first inactive region and a second inactive region, wherein the first and second inactive regions are separated by the active region; and a slotless phase winding comprising a plurality of conductive elements, wherein each conductive element comprises a conductor provided in an insulating housing, and wherein the slotless phase winding is arranged in a serpentine structure comprising: a first active segment in which the conductive elements extend across the active region from the first inactive region to the second inactive region; a second active segment in which the conductive elements extend across the active region from the second inactive region to the first inactive region; and an inactive segment coupling the first active segment to the second active segment, wherein the inactive segment comprises a turn provided in the second inactive region, and wherein at least one of the conductive elements is twisted in the second inactive region.