Electric Machine Asymmetric Stator Teeth Torque

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Solution Overview

Problem

The manufacturing costs of electrical machines are high due to complex coil winding processes, and existing designs do not efficiently optimize magnetomotive force and torque production.

Innovation Solution

A synchronous machine design where not all stator teeth are wound with coils, with wider main stator teeth and narrower auxiliary stator teeth, allowing for increased magnetomotive force and torque without coil saturation, and simplifying the manufacturing process by reducing the number of coils required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If coils are wound around every stator tooth, then the magnetomotive force and torque production are maximized, but the manufacturing complexity and cost increase significantly

Engineering Contradiction:
Improvetorque productionVSAvoidmanufacturing complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The stator teeth are segmented into two distinct types: wound stator teeth with coils and unwound stator teeth without coils. This segmentation allows the machine to achieve adequate torque production while significantly reducing the number of coils required, thereby simplifying manufacturing processes and reducing costs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different stator teeth are given different properties - some teeth have coils wound around them while others remain unwound. This local differentiation optimizes the distribution of magnetomotive force across the stator, maintaining effective torque production in critical areas while reducing overall complexity.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the number of coils is reduced, then manufacturing costs decrease, but the magnetomotive force and torque production may be compromised

Engineering Contradiction:
Improvemanufacturing costVSAvoidmagnetomotive force
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The width of wound stator teeth is increased compared to unwound stator teeth. This parameter change compensates for the reduced number of coils by enhancing the magnetomotive force generation capability of the wound teeth, thereby maintaining adequate torque production while reducing overall manufacturing costs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The stator teeth are designed with asymmetric width distribution - wound stator teeth are wider than unwound stator teeth. This asymmetric design optimizes the magnetic flux distribution and magnetomotive force generation, ensuring that the reduced number of coils does not compromise torque production.

Inventive Principle:
Principle #4Asymmetry

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 increases the average torque by approximately 6.4% and reduces manufacturing costs by simplifying the coil winding process while maintaining or improving magnetic flux and torque performance.

Implementation Method 1

The rotor has a plurality of rotor poles, which are preferably formed by means of permanent magnets

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

a coil is wound around each stator tooth, where N is a natural number

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 3

a magnetomotive force (MMK), which can be formed by means of an electrical current supply to the coils

Methodology Applied
Scientific EffectMagnetomotive force: Electromagnet

Data Source

PatentEP2584671B1Electric machine
Publication Date: 2020.08.05 ROBERT BOSCH GMBH
  • EP2584671B1 patent drawingFigure 1
  • EP2584671B1 patent drawingFigure 2
  • EP2584671B1 patent drawingFigure 3

AI summary

The electric machine (101) has a rotatably mounted rotor (103) provided with a rotor poles (107). The stator (109) is arranged with stator teeth (111). The coil (113) is wound between two stator teeth. The width of the two wound stator teeth is greater than a width of the uncoiled stator tooth. The phase is assigned to the coil. Each phase is connected with power converter. The ratio of the width of a wound stator tooth to the width of the stator tooth uncoiled is set to specific value.