Rotary Electric Machine Stator Winding Noise Reduction
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Solution Overview
Problem
Conventional rotary electric machines with wave windings experience uneven conductor wire distribution in slots, leading to wind-splitting noise due to differing turn counts in parallel and series connections, which affects output characteristics.
Innovation Solution
A rotary electric machine design where two three-phase stator windings with different turn counts are connected in series, with each winding portion configured into wave windings and distributed across slots to equalize conductor wire count, reducing unevenness and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If wave windings with different turn counts are used in parallel and series connections to increase output, then output characteristics are improved, but unevenness occurs on the inner circumferential surfaces of coil end groups generating wind-splitting noise
Solution Approach 1:
The patent applies local quality by differentiating the mounting locations of winding portions. Specifically, odd-numbered winding portions (U1-1, V1-1, W1-1 and U2-2, V2-2, W2-2) are mounted in slots of a first group, while even-numbered winding portions (U1-2, V1-2, W1-2 and U2-1, V2-1, W2-1) are mounted in slots of a second group. This spatial differentiation ensures that all slots contain the same total number of conductor wires (m+n), creating uniform coil end groups that eliminate wind-splitting noise while maintaining the different turn count configuration for enhanced output.
2Ease of manufacture
If concentrated windings are used instead of wave windings, then turn counts can be changed easily to solve cyclic currents and achieve desired output, but the complexity of the winding structure increases
Solution Approach 1:
The patent segments the stator winding into multiple independent winding portions (U1-1, U1-2, U2-1, U2-2, etc.) that can be independently configured with different turn counts. Each winding portion is a complete wave winding that can be independently adjusted, allowing flexible turn count configuration without increasing overall structural complexity. This segmentation enables easy adjustment of cyclic current issues and output characteristics while maintaining the simplicity of wave winding construction.
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 design suppresses the formation of unevenness on the inner circumferential surfaces of coil end groups, reducing wind-splitting noise and enhancing output by ensuring equal conductor wire distribution across slots, while simplifying manufacturing by omitting complex neutral point connections.
Implementation Method 1
a stator including: a stator core in which slots are formed at a ratio of two slots per phase per pole; and a first three-phase stator winding and a second three-phase stator winding that are mounted into the stator core, the stator being supported by the housing so as to surround the rotor
Data Source
AI summary
A stator winding is configured by connecting a first three-phase stator winding and a second three-phase stator winding in parallel. A U1-phase winding of the first three-phase stator winding is configured by connecting a U1-1-phase winding portion and a U1-2-phase winding portion in series, and a U2-phase winding of the second three-phase stator winding is configured by connecting a U2-1-phase winding portion and a U2-2-phase winding portion in series. The U1-1-phase winding portion and the U2-2-phase winding portion are m-turn wave windings, and the U2-1-phase winding portion and the U1-2-phase winding portion are n-turn wave windings (where n does not equal m). The U1-1-phase winding portion and the U2-1-phase winding portion are mounted into a first slot group, and the U1-2-phase winding portion and the U2-2-phase winding portion are mounted into a second slot group.