Stator Winding Harmonic Reduction via Segmented Coil Design
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Solution Overview
Problem
Three-phase single-wound concentric stator windings in electrical machines produce a wide spectrum of high space excitation harmonics, leading to reduced electromagnetic torque, increased differential reactance, losses, heating, vibration, and noise, especially in machines with a small number of stator slots, and are limited in applicability due to specific slot configurations.
Innovation Solution
A three-phase stator winding design with coils of varying widths and turns, arranged in a specific configuration to minimize high space excitation harmonics, allowing for sinusoidal magnetic field distribution, and adaptable to machines with odd numbers of slots per pole and phase, reducing harmonic amplitudes and improving operational characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-wound concentric stator windings are used, then the winding structure is simple and easy to manufacture, but high space excitation harmonics are generated leading to reduced electromagnetic torque and increased losses
Solution Approach 1:
The stator winding is divided into multiple independent windings (first stator winding and second stator winding) with different numbers of poles. Each winding generates magnetomotive forces that are combined to produce the total magnetic field. This segmentation allows harmonic cancellation while maintaining manufacturing simplicity through modular winding structures.
Solution Approach 2:
Different regions of the stator winding are designed with different local characteristics - the first stator winding has poles positioned at specific angles while the second stator winding has poles at different angles. This local differentiation in pole positioning creates complementary magnetomotive force distributions that cancel harmonics while preserving fundamental magnetic field quality.
2Ease of manufacture
If single-wound concentric stator windings are used, then the manufacturing process is simplified, but differential reactance and losses increase due to harmonic excitation
Solution Approach 1:
The stator winding system is segmented into multiple independent windings with different pole configurations. This segmentation enables the cancellation of high space excitation harmonics through proper phasing and positioning, thereby reducing eddy current losses and differential reactance while keeping the manufacturing process relatively simple through standardized winding techniques.
Solution Approach 2:
The invention employs asymmetric pole positioning between the first and second stator windings. The poles of the two windings are arranged at different angular positions, creating an asymmetric magnetic field distribution that cancels harmonic components. This asymmetric arrangement reduces energy losses while maintaining ease of manufacture through conventional winding methods.
3Device complexity
If conventional stator windings are used, then the winding design is straightforward, but vibration and noise increase due to high space excitation harmonics
Solution Approach 1:
The stator winding is segmented into multiple windings with different pole numbers and angular positions. This segmentation creates multiple magnetomotive force waves that interfere destructively with harmonic components, thereby reducing vibration and noise caused by high space excitation harmonics while keeping the winding design relatively straightforward.
Solution Approach 2:
The invention uses the concept of counterbalancing harmonic magnetomotive forces by introducing a second stator winding with poles positioned at specific angles relative to the first winding. The magnetomotive forces from the two windings act as counterweights that cancel each other's harmonic components, reducing vibration and noise without significantly increasing design complexity.
4Device complexity
If single-wound concentric stator windings are used, then the winding configuration is simple, but the applicability is limited to specific slot configurations
Solution Approach 1:
The invention creates a universal stator winding system that can be applied to various slot configurations by using multiple windings with different pole numbers. The first and second stator windings can be configured to work together in different combinations, enabling the same basic winding structure to serve multiple machine designs with different slot and pole arrangements, thereby increasing versatility while maintaining configuration simplicity.
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 winding significantly weakens high space excitation harmonics, enhancing electromagnetic torque, reducing losses and noise, and enabling wider applicability, including in submersible motors with limited stator diameters, by optimizing coil placement and turn distribution.
Implementation Method 1
Each of the single phase windings along the double polar pitch of the stator is made by coils... The action of high space excitation harmonics of magnetomotive force leads to the decrease of electromagnetic torque
Implementation Method 2
The active sides of the coils along the polar pitch are located in the nearby Z/2pm slots and completely fill the whole volume of the slots
Data Source
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AI summary
The invention refers to the sphere of electrical engineering in particular to stator windings of three-phase alternating current electrical machines and may be used for manufacturing of synchronous generators, synchronous and asynchronous motors. The technical result is significant weakening of high space excitation harmonics of magnetic field, approximation of magnetic field distribution in machine gaps to sinusoidal distribution. Stator winding of alternating current electrical machines contains three single phase windings, made up by the equal quantity of the coils placed in the slots and connected with each other in accordance with similar diagrams that ensure spatial shift of the axes of the windings relative to each other by 120 degrees. At that each of the single phase windings along the double polar pitch of the stator is made by 2Z/2pm coils that contain Z/2pm groups with the same number of coils in groups. Each coil group is made with different width of the coils it consists of and different number of turns that constitute the coils as compared with the other groups of coils. At that the coils of one group are made with minimal width and have got minimal number of turns. The width and the number of turns of the coil of each subsequent group are designed with different width and number of turns of the coils of the previous group. At that the coils of these groups are located concentrically relative to the coils with minimal width and minimal number of turns. The parts of the slots volume that are free after laying of the coils of this single phase winding are used for placement of the coils of the two other single phase windings made in a similar manner.