Reluctance Motor Rotor Insert Disk for High-Speed Stability

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Solution Overview

Problem

Conventional reluctance rotors are not suitable for high-speed applications, particularly in motor vehicles, due to mechanical instability caused by non-magnetic areas created by punching out flux-conducting sections, which limits their speed capability to below 3,000 revolutions/minute.

Innovation Solution

The introduction of insert disks made of polymers or woven fabrics between rotor laminations to bridge non-magnetic areas, providing mechanical stabilization by distributing centrifugal forces radially and maintaining magnetic properties, allowing for higher speed operation by connecting flux-guiding sections across non-magnetic areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-magnetic areas are created by punching out flux-conducting sections to provide magnetic flux barriers, then magnetic performance is improved, but mechanical stability deteriorates

Engineering Contradiction:
Improvemagnetic performanceVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies composite materials by combining rotor laminations with insert disks made of different materials (steel, polymer, or fabric). The insert disks are positioned in the non-magnetic areas between flux-conducting sections, creating a composite structure that provides both magnetic functionality and mechanical reinforcement. This composite approach allows the rotor to maintain magnetic performance while gaining the mechanical strength needed for high-speed operation.

Inventive Principle:
Principle #40Composite materials

2Power

If punched portions are created to form strip-shaped flux-conducting sections, then torque yield is improved, but mechanical stability deteriorates

Engineering Contradiction:
Improvetorque yieldVSAvoidmechanical stability
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The rotor lamination is segmented into multiple strip-shaped flux-conducting sections separated by non-magnetic areas. The insert disks are then placed in these non-magnetic areas to mechanically connect the segmented sections. This segmentation allows for high torque yield through optimized flux paths while the insert disks provide the mechanical continuity needed to withstand centrifugal forces at high speeds.

Inventive Principle:
Principle #1Segmentation

3Reliability

If rotor laminations are stacked to form a laminated core, then electrical insulation is improved, but mechanical stability deteriorates

Engineering Contradiction:
Improveelectrical insulationVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The insert disks act as intermediary elements between the rotor laminations. These disks are positioned at specific locations within the laminated core structure, providing mechanical reinforcement at critical points without disrupting the electrical insulation between laminations. The insert disks bridge the non-magnetic areas and connect flux-conducting sections across multiple laminations, enhancing overall mechanical stability while preserving the electrical insulation properties of the laminated structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables reluctance motors to operate at speeds greater than 5,000 revolutions/minute, enhancing mechanical stability and maintaining magnetic performance, making them suitable for electric vehicle drives.

Implementation Method 1

When the rotor rotates, centrifugal forces act on the individual flux guide sections, which act radially outwards on these individual areas of the rotor lamination away from the axis of rotation

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

Each layer of the laminated core therefore has a magnetically conductive rotor lamination, with a plurality of flux-conducting sections for a magnetic flux being formed by punching

Methodology Applied
Scientific EffectMagnetic flux conduction: Magnetic Field

Implementation Method 3

The non-magnetic areas act as magnetic flux barriers and each preferably extend between two adjacent q-axes of the rotor in the circumferential direction

Methodology Applied
Scientific EffectMagnetic flux barrier: Magnetic Field

Data Source

PatentEP2793362B1Reluctance motor and corresponding rotor
Publication Date: 2015.06.17 SIEMENS AG
  • EP2793362B1 patent drawingFigure 1
  • EP2793362B1 patent drawingFigure 2
  • EP2793362B1 patent drawingFigure 3~4

AI summary

The invention relates to a rotor (10) for a reluctance motor, wherein the rotor (10) comprises a laminated core (14) consisting of several electrically insulated layers (16), each of which has at least one magnetically conductive rotor lamination (18) and in which several flux guide sections (24) are formed by the at least one rotor lamination (18), which are separated from one another by a non-magnetic region (22). The invention is based on the objective of enabling high torque and high rotational speed. For this purpose, an insert disk (32) is arranged between at least two of the layers (16), which is connected to at least two flux guide sections (24) of one or both of the layers (16) between which it is arranged, thereby connecting these flux guide sections (24) to one another across the non-magnetic region (22) located between them.