Stator Winding Segmentation for Voltage Stress Reduction
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Solution Overview
Problem
Conventional electric machine winding arrangements face challenges with non-uniform air gaps due to rotor eccentricity, leading to imbalanced magnetic flux, increased vibration, and noise, while also experiencing high wire crossing voltages that can cause premature machine failure.
Innovation Solution
A rotational electric machine stator configuration where coils are arranged in a specific series and parallel coupling to distribute the phase voltage evenly, reducing the maximum possible wire crossing voltage and mitigating the effects of non-uniform air gaps by distributing coil connections to minimize imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional adjacent pole winding arrangement is used, then the machine structure is simple, but the wire crossing voltage becomes excessively high (1Vp) causing premature failure
Solution Approach 1:
The patent divides the phase winding into multiple separate circuits (first circuit with coils C1-C4, second circuit with coils C8-C5, third circuit with coils C6-C7) instead of using a single continuous winding. This segmentation distributes the voltage stress across multiple paths, reducing the maximum wire crossing voltage from 1Vp in conventional arrangements to 0.75Vp, thereby improving reliability while maintaining structural simplicity.
2Reliability
If skip-pole winding arrangement is used, then the wire crossing voltage is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by making specific coils (C1, C6, C8) discontinuous while keeping others continuous, and by strategically positioning the discontinuous coils at specific locations around the stator. This localized modification achieves the voltage reduction benefit of skip-pole winding (0.75Vp maximum) without requiring complete reconfiguration of all coils, thus maintaining ease of manufacture while improving reliability.
3Force
If coils are arranged to face non-uniform air gap, then the magnetic flux becomes imbalanced, but the vibration and noise increase
Solution Approach 1:
The patent segments the phase winding into multiple circuits with discontinuous coils strategically positioned to face different portions of the air gap. This segmentation allows each circuit to contribute to balancing the magnetic flux distribution across the non-uniform air gap, thereby reducing the imbalanced forces that cause vibration and noise while maintaining effective magnetic coupling.
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 proposed configuration reduces vibration and noise associated with non-uniform air gaps and decreases the maximum possible wire crossing voltage to 0.75Vp, compared to 1Vp in conventional skip-pole wound machines, thereby enhancing the operational stability and longevity of the electric machine.
Implementation Method 1
the coils 16 of the first 18 and second 20 circuits generally cooperate to generate a magnetic field for driving the rotor 12
Implementation Method 2
the magnetic flux in the air gap 22 faced by, for example, the first group is generally higher than the magnetic flux in the air gap 22 faced by the second group
Data Source
AI summary
Rotational electric machine stator winding arrangement characterized, inter alia, by at least one coil of each parallel circuit being discontinuous with the other coils of the corresponding circuit, and by coils configured to accept phase voltage not being adjacent coils having a point at the lowest potential of a corresponding circuit.