Stator Concentrated Winding Layout for Lower Interphase Voltage
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Solution Overview
Problem
Poly-phase AC electric machines with concentrated winding layouts face challenges in managing voltage differences between phases housed in the same slot, particularly in larger machines like generators for offshore wind turbines, necessitating thick phase separators to insulate phases effectively.
Innovation Solution
A concentrated star-connected winding layout with coils wound in alternating directions and specific interconnections between phases, minimizing voltage differences, allowing for reduced or eliminated phase separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional distributed windings are used, then the machine can be manufactured with standard techniques, but the power density and efficiency are limited due to leakage flux and harmonics
Solution Approach 1:
The winding is segmented into distinct concentrated groups per phase, with each phase having its own independent winding set. This segmentation allows for optimized magnetic flux paths while maintaining manufacturing feasibility through standardized modular assembly processes.
Solution Approach 2:
The patent transitions from the traditional distributed spatial arrangement of windings to a concentrated dimensional arrangement where multiple coils are stacked in the same spatial location. This dimensional change optimizes the magnetic coupling and reduces leakage flux while maintaining manufacturability through adapted winding techniques.
2Loss of energy
If concentrated windings are implemented, then efficiency and power density improve, but manufacturing and assembly become more difficult
Solution Approach 1:
The concentrated winding is divided into modular phase groups that can be manufactured and assembled independently. This segmentation enables standardized production processes for each phase while achieving the efficiency benefits of concentrated winding configuration.
Solution Approach 2:
The winding structure is designed to allow preliminary assembly of coil groups before final installation in the stator. This preliminary action simplifies the manufacturing process by enabling pre-assembly and quality control outside the constrained stator assembly environment.
3Ease of operation
If distributed windings are used, then manufacturing is easier, but torque ripple and acoustic noise increase
Solution Approach 1:
The stator winding is segmented into distinct concentrated phases with clear spatial separation, which simplifies the magnetic flux distribution and reduces torque ripple. This segmented structure achieves operational smoothness while maintaining manageable structural complexity through standardized phase modules.
4Weight of moving object
If conventional winding layouts are used, then the stator design is simple, but the machine size and weight increase for the same power output
Solution Approach 1:
The patent employs a dimensional transition in winding arrangement, concentrating multiple coils in the same spatial footprint to reduce the overall machine size. This dimensional optimization achieves compact weight without excessive complexity through systematic phase grouping and standardized construction methods.
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 layout reduces voltage differences between phases, enabling thinner or absent phase separators, enhancing electrical insulation efficiency and flexibility in winding configurations.
Implementation Method 1
The electrical ac machine includes a three-phase concentrated winding layout consisting of three independent and identical phase windings (U, V, W) distributed along the stator
Implementation Method 2
The electrical ac machine is a four-pole machine with 18 slots and 36 coils, where the concentrated winding layout reduces leakage flux and harmonics
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An electrical AC machine (31) comprises: a stator (20) having a plurality of teeth (101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112) distributed along a circumferential direction (X) and a plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), a rotor (30) rotatable opposite with respect to the stator (20) a concentrated winding layout (100) comprising a plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212) respectively wound on the plurality of teeth (101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112) and belonging to at least six phases (A1, A2, B1, B2, C1, C2), the coils being wound so that when considering three adjacent coils the intermediate coil is interposed between one coil wound in the same direction of the intermediate coil and another coil wound in the opposite direction of the intermediate coil, wherein the plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) comprises a first set of odd/even slots (1, 3, 5, 7, 9, 11) and a second set of even/odd slots (2, 4, 6, 8, 10, 12), each coil (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212) in the first set of slots (1, 3, 5, 7, 9, 11) being connected to an input conductor (401, 402, 403, 404, 405, 406) of one phase (A1, A2, B1, B2, C1, C2) or to a neutral conductor (N1, N2), each of the interconnections (301, 302, 303, 304, 305, 306) extending between two respective slots of the second set of slots (2, 4, 6, 8, 10, 12).