Rotating Electric Machine Mixed Phase Band Winding
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Solution Overview
Problem
Existing rotating electric machines with fraction slot configurations face challenges in reducing noise and vibration due to excitation forces in lower-order spatial deformation modes, as the magnetomotive force distribution is not uniform, leading to increased noise and vibration across a broader range of rotation frequencies, particularly in electric cars and hybrid vehicles.
Innovation Solution
The rotating electric machine incorporates a stator with coils in a mixed phase band group configuration, where basic phase bands are stacked in a specific radial direction to ensure uniform magnetomotive force per pole, achieved by deviating coil groups by predetermined slots, resulting in a uniform magnetomotive force distribution and reduced excitation forces in lower-order spatial deformation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fraction slot configuration is used with conventional winding arrangements, then the number of slots per pole per phase is reduced, but the magnetomotive force distribution becomes non-uniform, generating excitation forces in lower-order spatial deformation modes that increase noise and vibration
Solution Approach 1:
The winding is divided into multiple layers (first layer, second layer, third layer) with different phase band arrangements. Each layer has basic phase bands deviated by specific slot numbers, creating a segmented structure that achieves uniform magnetomotive force distribution across poles while maintaining fraction slot configuration
Solution Approach 2:
The phase bands in different layers are deliberately arranged asymmetrically with respect to slot positions. The first layer has basic phase bands at specific slots, the second layer deviates by a predetermined number of slots, and the third layer deviates by a different predetermined number of slots, creating an asymmetric pattern that balances the overall magnetomotive force distribution
2Reliability
If windings are deviated by predetermined slots to reduce torque ripple, then torque ripple is reduced, but the magnetomotive force magnitude varies in a 4:3:3:4 pattern that still generates excitation forces in lower-order spatial deformation modes
Solution Approach 1:
The solution moves from a single-layer winding arrangement to a multi-layer radial structure. By adding the radial dimension with three distinct layers, each having different circumferential deviations, the patent achieves uniform magnetomotive force distribution in both circumferential and radial directions, eliminating the 4:3:3:4 variation pattern
Solution Approach 2:
The basic phase band structure is copied across three layers with different deviations. Each layer contains complete sets of basic phase bands for all phases, but positioned at different slot locations. This copying approach with varied positioning ensures that the combined magnetomotive force from all layers is uniform across all poles
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 enhances rotational symmetry of the magnetomotive force distribution, reducing noise and vibration within the operational frequency range by minimizing excitation forces in low-order spatial deformation modes, thus improving the motor's performance and reducing resonance chances.
Implementation Method 1
a plurality of slots in which coils formed of conductive wires are stored; and a rotor facing the stator and having a plurality of magnetic poles
Data Source
AI summary
A rotating electric machine includes: a stator having slots in which coils formed of conductive wires are stored; and a rotor facing the stator and having magnetic poles. The rotating electric machine has a fraction slot configuration or an integer slot configuration. The coils configure a mixed phase band group in which a first, second and third basic phase band groups are stacked in this order in a radial direction of the slots. In the mixed phase band group, a magnitude of magnetomotive force of each phase per pole is uniform, and, when the number of layers of the first, second and third basic phase band groups in the radial direction are denoted by m1, m2 and m3, respectively a relationship of 0<2×m2/(m1+m3) is satisfied.