Flat Wire Motor Stator Slot Structure to Suppress Skin Effect
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Solution Overview
Problem
The existing methods for reducing eddy current loss in flat wire motors, such as decreasing the cross-sectional area of flat wire conductors, lead to increased DC resistance and design limitations, affecting motor efficiency in low-speed and low-torque conditions and complicating universal design for new energy vehicle motors.
Innovation Solution
A stator structure with an avoidance layer made of the same material as the stator core, positioned between the slot opening and the first layer of flat wire conductor, increases the distance between the conductor and the slot opening, reducing the skin effect and eddy current loss by acting on the avoidance layer during high-frequency magnetic field changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cross-sectional area of the flat wire conductor is reduced to decrease eddy current loss in high-speed section, then the eddy current loss is reduced, but the DC resistance increases and motor efficiency in low-speed and low-torque section deteriorates
Solution Approach 1:
The patent applies local quality by introducing an avoidance layer made of non-magnetic material at specific locations (between the slot opening and the first layer of flat wire conductor) rather than changing the entire conductor structure. This localized intervention reduces eddy current loss in the high-speed section where skin effect is most prominent, while preserving the original conductor cross-sectional area and DC resistance characteristics for low-speed operation.
Solution Approach 2:
The avoidance layer acts as an intermediary element between the slot opening and the flat wire conductor. This non-magnetic material layer mediates the magnetic field interaction, reducing the skin effect on the conductor without requiring changes to the conductor itself, thereby maintaining both low-speed and high-speed performance.
2Loss of energy
If the number of flat wire conductor layers per slot is increased to reduce eddy current loss, then the eddy current loss is reduced, but the design flexibility is limited and stator core with different slot numbers is required
Solution Approach 1:
The patent segments the solution by introducing a separate avoidance layer component that can be independently designed and positioned. This segmentation allows the avoidance layer to be added to existing stator core designs without requiring changes to the slot number or conductor configuration, thereby maintaining design flexibility across different motor platforms.
Solution Approach 2:
The avoidance layer design is universal and can be applied to stator cores with different slot numbers, pole numbers, and conductor configurations. This multi-functional approach allows the same avoidance layer concept to reduce eddy current loss across various motor designs without requiring redesign of the stator core, enhancing adaptability and platformization.
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
This solution effectively reduces eddy current loss, improves motor efficiency, and enhances design flexibility by allowing for adjustments in the number of flat wire conductor layers without altering the stator core design, while also reducing copper consumption and heat aggregation.
Implementation Method 1
the skin effect caused by the high-frequency change of the magnetic field
Implementation Method 2
reducing the eddy current loss of the flat wire conductor
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A stator structure and a flat wire motor are provided. The stator structure comprises a stator core (11,31), stator windings (12,32) and an avoidance layer (13,33). The stator core (11) has an inner cylinder cavity (111), and a plurality of iron core slots (112) arranged at intervals in a circumferential direction on an end face of the stator core (11). The iron core slot (112) is communicated with the inner cylinder cavity (111) via a slot opening (113). The stator windings (12) have a plurality of layers of flat wire conductor (121) wound in the iron core slots (112). The avoidance layer (13) is located between the slot opening (113) and a first layer of flat wire conductor (121) in a radial direction of the stator core (11). During the operation of the flat wire motor with this stator structure, the skin effect caused by the high-frequency change of the magnetic field will act on the avoidance layer (13), thereby reducing the skin effect generated at the first layer of flat wire conductor (121), weakening the influence of the slot leakage flux on the first layer of flat wire conductor (121), reducing the eddy current loss of the first layer of flat wire conductor (121), and further reducing the eddy current loss of the whole motor, and thus achieving the technical effect of improving the motor efficiency.