Electrical Machine Concentrated Winding Radial Protrusions

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Solution Overview

Problem

Existing small-sized permanent magnet machines with slotless stator topologies face challenges in achieving optimal performance for high-speed and high-power applications due to limitations in winding configurations, leading to reduced power density and increased complexity in production, especially at diameters below 10 mm.

Innovation Solution

A concentrated winding solution using a single body with radial protrusions made of electrically insulating material, supporting coils and allowing for precise positioning and easy assembly, without the need for additional insulation, and incorporating a ferromagnetic outer casing to enhance torque constant through homogeneous distribution of ferromagnetic particles in the air gap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If slotless stator topology is used in small-sized machines, then torque ripple and vibrations are minimized, but power density is reduced

Engineering Contradiction:

Improvetorque rippleVSAvoidpower density

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The stator body is segmented into multiple radial protrusions (typically 3-6), each carrying a concentrated coil. This segmentation allows the slotless topology to maintain its smooth operation benefits while creating distinct magnetic zones that improve power density through better flux concentration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces localized ferromagnetic protrusions at specific radial positions around the stator circumference. These localized ferromagnetic regions concentrate magnetic flux where needed, improving power density without compromising the overall slotless topology that minimizes torque ripple.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If concentrated winding with separate coils is used, then winding flexibility is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvewinding flexibilityVSAvoidassembly complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention merges the coil winding and support structure into an integrated concentrated winding assembly. The coils are pre-assembled on a support structure with precise positioning features, then the entire assembly is inserted into the stator body as a single unit, dramatically simplifying manufacturing while maintaining winding flexibility.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The concentrated coils are pre-assembled and positioned on the support structure before insertion into the stator. This preliminary assembly ensures precise positioning and electrical insulation are achieved during manufacturing, reducing on-site assembly complexity and improving production efficiency.

Inventive Principle:

Principle #10Preliminary action

3Power

If additional insulation and ferromagnetic particles are added to enhance torque constant, then magnetic performance is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvetorque constantVSAvoidmanufacturing process

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The invention uses composite material technology by incorporating ferromagnetic particles into an insulating matrix material. This creates a single composite material that provides both electrical insulation and magnetic flux concentration properties, eliminating the need for separate insulation layers and ferromagnetic particle applications, thus reducing manufacturing steps while enhancing torque constant.

Inventive Principle:

Principle #40Composite materials

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 solution simplifies the winding process, enhances torque constant, reduces magnetic losses, and achieves robust structure assembly, demonstrating notable gains in performance with relative permeabilities less than 100, which is economically advantageous and less restrictive in terms of production processes.

Implementation Method 1

the use of a ferromagnetic material, in particular a plastic material with addition of ferromagnetic particles, for the outer casing 2 of the stator

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

said body is extended by three, four or six radial protrusions made of an electrically insulating material

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP3934060A1Electrical machine with concentrated winding

Publication Date: 2022.01.05 MOVING MAGNET TECH

Figure 1a~1d
Figure 2a~2c
Figure 3~4

AI summary

The present invention relates to an electrical machine comprising a tubular rotor magnetized to exhibit circumferential polar alternations, and a stator having a body (4) through which a channel (16) passes, the inner cross-section of which corresponds substantially to the outer cross-section of said rotor. Said body (4) supports a plurality of coils (5a to 5c). Said stator is surrounded by an outer ferromagnetic casing (2), characterized in that said body (4) is extended by three, four, or six radial protrusions made of an electrically insulating material. In cross-section, the body (4) has a longitudinal core (20 to 22) for receiving a coil. Said core (16) is extended by a peripheral extension (30 to 32) having an outer surface complementary to the inner surface of said casing (2) and covering the wound area. The invention also relates to a method for manufacturing such an electrical machine.