Odd-Layer Stator Winding Layout for Lower Harmonics and Noise
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Solution Overview
Problem
Conventional stator windings with odd number of layers face issues of higher harmonics, motor noise, and limited assembly flexibility due to hair-pin coils occupying radial inner space, necessitating one-sided rotor assembly.
Innovation Solution
A stator assembly with U-, V-, and W-phase windings arranged in odd layers, utilizing short pitch connections and alternating long and short pitch hair-pin coils, allowing flexible rotor assembly and reducing harmonics and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If full pitch connections are used in odd number of layers of flat wire windings, then the winding structure is simplified, but the 5th and 7th harmonics increase causing higher motor noise
Solution Approach 1:
The patent changes the connection parameter from full pitch to short pitch by introducing a pitch factor k < 1. This modifies the harmonic content of the winding, specifically reducing the 5th and 7th harmonics while maintaining the odd number of layers structure. The short pitch connection achieves this by connecting coils that are not exactly one pole pitch apart, thereby altering the electromagnetic harmonic distribution.
2Device complexity
If hair-pin coils are arranged in the same layer at both welding and non-welding ends, then the winding layout is simplified, but the radial inner space of stator slot is occupied requiring one-sided rotor assembly
Solution Approach 1:
The patent segments the winding into two distinct parts: welding end coils and non-welding end coils. The welding end coils are arranged in the same layer to maintain structural simplicity, while the non-welding end coils are arranged in different layers to free up the radial inner space. This segmentation allows the rotor assembly to be installed from either side of the stator, thereby improving assembly flexibility without significantly complicating the overall winding layout.
3Adaptability or versatility
If odd number of layers of flat wire windings are used, then technical requirements for various motors are met, but full pitch connections result in higher harmonics and noise
Solution Approach 1:
The patent maintains the odd number of layers configuration to meet diverse motor technical requirements while introducing short pitch connections as a modifying parameter. By adjusting the pitch factor and coil arrangement, the harmful harmonics are reduced without sacrificing the adaptability of the odd-layer winding structure for different motor applications.
Data Source
AI summary
A stator assembly is provided that includes a stator core and stator windings having a U-phase winding, a V-phase winding, and a W-phase winding. An n-number of stator slots are on an inner circumferential surface of the stator core, each stator slot is divided into an m-number of accommodating layers along a radial direction of the stator core, the U-phase winding is laid in the stator slot and is arranged in the same layer in an m-th accommodating layer and arranged across layers in other accommodating layers, n is a multiple of 6, and m is an odd number greater than 3. The U-phase winding includes first and second branch windings formed by connecting the same number and type of coils in series; the V-phase winding is obtained by rotating the U-phase winding clockwise by 120°, and the W-phase winding is obtained by rotating the U-phase winding clockwise by 240°.