Electrical Generator End-Winding Tilt for Joule Loss Reduction
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Solution Overview
Problem
Electrical machines, such as generators in wind turbines, face inefficiencies due to electromagnetic losses, particularly copper losses in stator conductors leading to high temperatures, which are exacerbated by long coil and end-winding lengths, necessitating an efficient cooling system and compact end-winding designs to minimize overhang and reduce heat generation.
Innovation Solution
The electrical machine incorporates a unique end-section design with three different winding types, where each coil comprises a combination of first, second, and third winding types, with specific tilt angles to minimize overhang length, allowing for a more compact arrangement and reduced joule losses, thereby enhancing efficiency and reducing cooling requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the coil and end-winding lengths are increased to accommodate high currents in large armatures, then the current carrying capacity is improved, but the temperature increases and efficiency decreases due to higher joule losses
Solution Approach 1:
The end-winding is divided into multiple parallel conductors instead of using a single thick conductor. This segmentation reduces the cross-sectional area of each individual conductor while maintaining the same total current carrying capacity, thereby reducing joule losses in the end-winding region.
Solution Approach 2:
The invention transitions from a planar winding arrangement to a three-dimensional configuration where conductors are arranged in multiple layers and directions. This allows for optimized current distribution and reduced path length, minimizing joule losses while maintaining high current capacity.
2Loss of energy
If the overhang length of the windings is reduced to improve efficiency and reduce cooling requirements, then the joule losses are minimized, but the manufacturing complexity increases due to the need for precise slot accommodation
Solution Approach 1:
Different sections of the winding are designed with different properties: the body sections have standard configurations for easy manufacturing, while the end sections are specifically optimized with reduced overhang and tailored geometries to minimize joule losses. This local differentiation allows both manufacturing ease and efficiency improvement.
Solution Approach 2:
The invention optimizes specific geometric parameters of the end-windings, such as the overhang length, conductor angle, and slot insertion depth, to achieve minimal joule losses. By carefully adjusting these parameters within manufacturing tolerances, the design achieves high efficiency without excessive manufacturing complexity.
3Ease of manufacture
If multiple different winding types with various end sections are used to accommodate slot arrangements, then the manufacturability is improved, but the overhang length increases resulting in higher joule losses
Solution Approach 1:
The invention uses a standardized end-section design that can be universally applied across different winding types and slot configurations. This universal end-section geometry minimizes overhang length and joule losses while being adaptable to various manufacturing requirements, eliminating the need for multiple specialized winding types.
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 reduces the overhang length and weight of the electrical machine, minimizing joule losses and improving efficiency by allowing for a more compact and effective cooling system, thus addressing the inefficiencies caused by electromagnetic losses.
Implementation Method 1
each coil comprising a first winding type, a second winding type and a third winding type in sequence... the body sections being joined electrically by conductive end sections
Implementation Method 2
copper losses in stator conductors... In the coils and in the end windings joule losses are transformed to thermal energy causing heating up the stator
Data Source
Figure 1
Figure 2
Figure 3~6
AI summary
The invention describes an electrical machine (4, 4'), in particular an electrical generator, with an armature (2) and at least one field magnet arrangement (3) separated by a gap from each other, whereby the armature (2) and/or the filed magnet arrangement (3 )comprises a plurality of coils (C1, C2, C3). Each coil (C1, C2, C3) comprises conductive body sections (10A, 10B, 20A, 20B, 30A, 30B), whereby the body sections (10A, 10B, 20A, 20B, 30A, 30B) of the coils (C1, C2, C3) are joined electrically by conductive end sections (10C, 20C, 30C). At least one of the end sections (20C) of at least one coil (C2) of the armature (2) is tilted in a direction away from the armature (2) towards the field magnet arrangement (3) and/or at least one of the end sections of at least one coil of the field magnet arrangement is tilted in a direction away from the field magnet arrangement (2) towards the armature (3). The invention also describes an armature (2) and/or field magnet arrangement (3) for a wind turbine (5), a wind turbine (5) with such an electrical machine (4) and the use of the electrical machine (4) as generator.