Five-Phase Generator Winding Layout for Noise Reduction

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Solution Overview

Problem

Multi-phase electrical machines, such as generators, face challenges with magnetic noise, flow noise, and manufacturing precision due to a high number of slots, which limits wire diameter and increases the likelihood of wire damage during assembly.

Innovation Solution

A five-phase electrical machine design with a stator core having a circumferential slot pitch and a winding arrangement where the number of slots corresponds to a multiple of the number of phases, allowing for larger wire diameters and improved manufacturing tolerance, using distributed windings and loop or wave windings with optimized slot widths and yoke heights to reduce noise and enhance robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a high number of phases (six-phase or two-times three-phase system) is used, then the magnetic noise is reduced, but the number of slots increases which limits the wire diameter and increases manufacturing complexity

Engineering Contradiction:
Improvemagnetic noiseVSAvoidnumber of slots
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the phase configuration parameter from six-phase or two-times three-phase to five-phase system. This parameter change reduces the number of slots required while maintaining noise reduction benefits, thereby allowing larger wire diameters and simplifying the overall device structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a specific winding arrangement where windings are distributed in layers at different radial positions within the stator slots. This local optimization of winding placement improves space utilization and allows for larger wire diameters in a five-phase configuration, resolving the contradiction between slot count and wire size.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If a high number of phases is used, then the magnetic noise is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvemagnetic noiseVSAvoidassembly precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

By changing the phase system from six-phase to five-phase, the patent reduces the number of windings and slots, which directly lowers the cumulative tolerance requirements. Fewer components mean fewer sources of manufacturing variation, thereby reducing the overall precision requirements while maintaining electromagnetic performance.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the number of slots is increased, then the number of phases is increased, but the wire diameter is limited and mechanical resilience is reduced

Engineering Contradiction:
Improvenumber of phasesVSAvoidmechanical resilience
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent optimizes the phase configuration parameter to five phases, which provides an optimal balance between electrical performance and mechanical strength. This configuration allows for larger wire diameters with adequate mechanical resilience while maintaining high adaptability for different applications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a layered winding arrangement where windings are positioned at different radial levels within the stator. This local structural optimization allows for larger individual wire diameters that enhance mechanical strength, while the five-phase configuration maintains the required electrical adaptability.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If prefabricated windings are used to simplify manufacturing, then assembly is easier, but the number of windings increases complexity

Engineering Contradiction:
Improveassembly processVSAvoidnumber of windings
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

By reducing the phase system to five phases, the patent decreases the total number of windings required compared to six-phase systems. This parameter change makes the use of prefabricated windings more practical and cost-effective, as fewer complex components need to be manufactured and assembled.

Inventive Principle:
Principle #35Parameter changes

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 design reduces magnetic and flow noise, improves performance and efficiency by minimizing ripple in the rectified generator voltage, and allows for a more cost-effective and precise manufacturing process with increased mechanical resilience and reduced assembly forces.

Implementation Method 1

electromagnetic forces create unwanted magnet noise

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a stator which has a core body having a circumferential slot pitch and a winding arrangement with a plurality of windings forming phases

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2115858B1Polyphase electrical machine
Publication Date: 2014.09.03 ROBERT BOSCH GMBH
  • EP2115858B1 patent drawingFigure 1
  • EP2115858B1 patent drawingFigure 2
  • EP2115858B1 patent drawingFigure 3~4

AI summary

The invention relates to a polyphase electrical machine, in particular a polyphase generator with a stator, which has a core element having a circumferential slot pitch and a winding arrangement with a plurality of windings. It is provided that each winding (45, 46, 47, 48, 49) and each slot (35, 36, 37, 38, 39) of the group of slots extending over a pole pitch is associated with one of the phases, and the windings (45, 46, 47, 48, 49) have winding sections (55) lying in associated slots (35, 36, 37, 38, 39), between which winding sections in each case one end winding connection (56) is formed, wherein the end winding connections (56) of different windings (45, 46, 47, 48, 49) are arranged radially with respect to one another in terms of position, and the number of phases is five. Furthermore, the invention relates to a method for producing a polyphase electrical machine.