Three-Layer Winding Structure for Torque Ripple Reduction
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Solution Overview
Problem
Conventional electric motors with fractional slot windings struggle to completely eliminate low-order harmonic components causing torque ripple, which reduces torque while increasing manufacturing complexity.
Innovation Solution
A three-phase alternating current electric motor with a three-layer winding arrangement in the stator, where the number of slots divided by the number of pole pairs is a fraction with an odd denominator, and windings are arranged in rotational symmetry at ±120 degrees across three layers to enhance the winding factor of the first order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If fractional slot winding arrangement is used to reduce torque ripple, then torque ripple is reduced, but winding factor of first order decreases resulting in reduced torque
Solution Approach 1:
The winding is divided into three distinct layers (first layer, second layer, third layer) with specific arrangements in each layer. This segmentation allows different harmonic components to be controlled independently, reducing torque ripple while maintaining the fundamental winding factor through optimized layer configurations.
Solution Approach 2:
Different regions of the winding (different layers and phases) are assigned different arrangement patterns. The first layer has U-phase, V-phase, and W-phase windings with rotational symmetry, while the second and third layers have shifted arrangements, creating local variations that cancel harmonics while preserving fundamental torque.
2Object-generated harmful factors
If conventional modifications to rotor core form or stator core form are made to reduce torque ripple, then torque ripple is reduced, but device complexity increases
Solution Approach 1:
The torque ripple reduction function is extracted from the mechanical structure ( rotor core form, stator core form, skew designs) and transferred to the electrical winding arrangement. By modifying only the winding configuration rather than the mechanical components, the solution achieves torque ripple reduction without increasing structural complexity.
Solution Approach 2:
The mechanical approach to torque ripple reduction (modifying rotor/stator core forms and skews) is replaced with an electrical approach (optimizing winding arrangement). This substitution maintains mechanical simplicity while achieving the desired torque characteristics through electromagnetic field optimization.
3Object-generated harmful factors
If pole number and slot number are optimized with high least common multiple to reduce torque ripple, then torque ripple is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention changes the winding arrangement parameters (layer configuration, phase distribution, slot positioning) rather than changing the fundamental motor parameters (pole number, slot number). This allows torque ripple reduction without requiring complex pole-slot combinations, maintaining ease of manufacturing while achieving performance improvement.
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 configuration effectively reduces torque ripple while maintaining high torque by optimizing the winding factor of the first order and lowering higher-order winding factors, thereby simplifying the motor structure and manufacturing process.
Implementation Method 1
a plurality of windings inserted into the slots and wound in the stator
Data Source
AI summary
In a three-phase AC electric motor, in each slot, any or some of the windings of six phases in total, including three phases of U, V, and W phases and opposite phases thereof, are arranged in three layers per slot. As the windings in first layers, of the three-layer windings, U, V, and W-phase windings are arranged so as to have rotational symmetry with one another at a mechanical angle of ±120 degrees. The windings in second layers have the same arrangement as in the first layers shifted by L slots, and the windings in third layers have the same arrangement as in the first layers shifted by L slots in a direction opposite to the arrangement of the windings in the second layers.