Multi-Branch Rectangular Stator Winding Without Circulating Current
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Solution Overview
Problem
Conventional rectangular conductor motors face challenges in designing a winding structure without circulating current, especially when increasing the number of parallel branches, which affects efficiency and noise due to phase differences in magnetic fields between branches.
Innovation Solution
A stator assembly with a multi-branch rectangular conductor winding is designed, where each branch has an equal number of conductors in each layer, and the arrangement of branches in different regions of the stator slots is optimized to eliminate phase differences, using specific configurations of rectangular conductor coils with crossover and welding parts to connect them, ensuring each branch passes through each layer equally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of parallel branches is increased to improve motor performance, then power density and efficiency are improved, but circulating current between branches occurs due to phase difference in magnetic fields
Solution Approach 1:
The patent applies local quality by differentiating the arrangement of conductors in different regions of the stator slots. Specifically, conductors in first region slots are arranged with a first number per layer while conductors in second region slots are arranged with a second number per layer, where these numbers differ. This localized differentiation ensures that each parallel branch passes through each layer an equal number of times, eliminating phase differences and circulating currents while maintaining high power density.
2Loss of energy
If conventional winding design with fewer parallel branches is used, then circulating current is avoided, but motor performance and power density are limited
Solution Approach 1:
The patent changes the parameter of conductor arrangement by introducing different numbers of conductors per layer in different regions. This parameter change allows the system to accommodate more parallel branches (up to 16 branches in embodiments) while maintaining balanced magnetic fields. The key parameter change is from uniform conductor distribution to region-specific conductor distribution, enabling both high performance and energy efficiency.
3Power
If rectangular conductor motors use more parallel branches to meet performance requirements, then power density increases, but it becomes impossible to design a winding structure without circulating current
Solution Approach 1:
The patent segments the stator slots into first region slots and second region slots, with each region having different conductor arrangement characteristics. This segmentation allows independent optimization of each region's conductor layout to achieve balanced parallel branch distribution. The segmentation approach simplifies the overall design process by breaking down the complex winding structure into manageable regional units with specific arrangement rules.
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 design inhibits circulating currents between branches, suppresses harmonics, and improves motor efficiency by ensuring no phase difference in magnetic fields between parallel branches.
Implementation Method 1
The plurality of hairpins is configured to occupy the n respective turn positions an equal number of times such that the respective conductor layers (L1, L2 ...) are electrically balanced
Data Source
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AI summary
The present disclosure discloses a stator assembly and motor. The stator assembly comprises a stator core (1) and a multi-branch rectangular conductor winding (3), an even number of stator slots are provided on an inner circumference of the stator core (1), and each of the stator slots is divided into multiple layers for accommodating rectangular conductors. The multi-branch rectangular conductor winding (3) is provided in the stator slots, and the multi-branch rectangular conductor winding (3) comprises B number of parallel branches, and B is an integer multiple of 4. The number of slots per phase per pole, Q, of the stator assembly is an odd number, and Q and B satisfy a relationship that both (Q+1)∗2/B and (Q-1)∗2B are integers. In the stator assembly of the present disclosure, by way of the special winding connection design, there is no phase difference of magnetic fields between the parallel branches, and each parallel branch equally passes through each layer in the stator slots, which fundamentally inhibits the generation of circulating current between the parallel branches, suppresses the harmonics, and improves the efficiency of the motor.