Reluctance Machine Rotor with Doped Non-Magnetic Structures

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Solution Overview

Problem

Existing dynamo-electric reluctance machines with ferromagnetically laminated rotors face challenges in achieving significant torque due to complex manufacturing processes and limited anisotropy, leading to high harmonics in the torque spectrum.

Innovation Solution

A rotor with a laminated core made of ferromagnetic laminations featuring alternating magnetic and non-magnetic areas, where non-magnetic structures are bonded via metallic doping on ferromagnetic sections, creating a stator winding system that interacts electromagnetically across an air gap with alternating magnetic and non-magnetic areas in the direction of movement, enhancing magnetic anisotropy and inductance differences between the d and q axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If non-magnetic structures are produced by casting or die-casting, then the rotor structure can be manufactured, but the manufacturing process becomes complex

Engineering Contradiction:
Improvemanufacturing process complexityVSAvoidstructural precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the manufacturing method from casting/die-casting to metallic bonding with doped particles, fundamentally altering how non-magnetic structures are created. This allows precise control of magnetic resistance through particle doping concentration and distribution while using simpler bonding processes instead of complex casting operations

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by doping non-magnetic metal particles into ferromagnetic sections, combining two material types with different magnetic properties. This composite approach enables precise control of magnetic anisotropy while simplifying the overall manufacturing process compared to pure casting methods

Inventive Principle:
Principle #40Composite materials

2Strength

If connecting webs are used between magnetic areas, then structural integrity is maintained, but magnetic anisotropy is reduced

Engineering Contradiction:
Improvestructural integrityVSAvoidmagnetic anisotropy
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies local quality by doping non-magnetic metal particles specifically in predetermined sections where connecting webs would normally be located. This creates localized non-magnetic regions that maintain structural integrity through particle reinforcement while preventing magnetic flux leakage, thereby preserving magnetic anisotropy in the overall rotor structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent replaces the mechanical connecting web structure with a metallic bond reinforced by doped non-magnetic metal particles. This substitution eliminates the need for physical connecting webs that would disrupt magnetic fields, while still providing structural integrity through the bonded particle-reinforced joints

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of energy

If the rotor circumference is made geometrically round, then air friction is reduced, but magnetic non-roundness is lost

Engineering Contradiction:
Improveair friction lossVSAvoidmagnetic field distribution
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies local quality by doping non-magnetic metal particles in specific predetermined sections of the rotor circumference rather than uniformly throughout. This creates localized magnetic barriers that provide magnetic non-roundness for proper flux guidance while maintaining a geometrically round overall rotor shape, thus reducing air friction losses

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent resolves the contradiction by operating in two dimensions simultaneously: the rotor maintains a round geometric shape in the spatial dimension for reduced air friction, while creating magnetic non-roundness through selective particle doping in the magnetic property dimension, achieving both goals through multi-dimensional design

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration results in increased torque and speed for rotary reluctance machines and higher power development in linear machines, reduced harmonics, and improved efficiency by minimizing air friction and allowing for adjustable torque ripple and anisotropy, suitable for various geometric dimensions and performance classes.

Implementation Method 1

the non-magnetic areas being realized by non-magnetic structures which are arranged in predetermined sections of the laminations by means of metallic bonding

Methodology Applied
Scientific EffectMetallic bonding: Welding

Implementation Method 2

a stator with a winding system which interacts electromagnetically with the runner across an air gap

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 3

A reluctance motor is known from US Pat. No. 3,671,789, the rotor of which attempts to produce different inductivities by means of axially running metal sheets

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 4

Basically, reluctance machines require different inductances in the longitudinal and transverse axis of the rotor

Methodology Applied
Scientific EffectMagnetic anisotropy: Anisotropy

Implementation Method 5

a laminated core stacked from ferromagnetic laminations

Methodology Applied
Scientific EffectLamination: Lamination

Data Source

PatentEP2768117B1Rotor of a reluctance machine
Publication Date: 2019.01.23 SIEMENS AG
  • EP2768117B1 patent drawingFigure 1~2
  • EP2768117B1 patent drawingFigure 3~5

AI summary

The rotor (3) has a stacked ferromagnetic sheets laminated core. Magnetic area (4) and non-magnetic area (5) are alternately provided in the sheets of the stacked ferromagnetic sheets laminated core. The non-magnetic areas are implemented by non-magnetic structures, and are provided by a metallic material that is fit in predetermined portions of the sheets. Plates of the rotor are produced by rapid prototyping process. An independent claim is included for a dynamo-electric reluctance machine.