Brushless Torque Motor Segmented Winding for Simultaneous Force Generation

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Solution Overview

Problem

Existing brushless torque motors with permanent magnets and stator windings struggle to achieve high power density while simultaneously generating torque and transverse forces, especially at low speeds, due to complex coil arrangements and the need for sensors, which compromise power density and increase production costs.

Innovation Solution

The motor design features electrically connected coils arranged within a stator division of 360 degrees divided by the number of winding strands, allowing for increased poles and efficient force generation using radial components of Maxwell forces, along with a structurally simple control system and adaptable pole numbers, enabling high power density and simultaneous torque and transverse force production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the number of magnetic poles in the stator is increased to achieve high power density, then power density is improved, but the ability to simultaneously generate torque and lateral force is lost

Engineering Contradiction:
Improvepower densityVSAvoidability to generate torque and lateral force simultaneously
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The stator winding is divided into multiple independent winding strands (at least four), each capable of being controlled individually or connected in star/ring configuration. This segmentation allows different strands to work independently for torque generation while others provide lateral force, resolving the contradiction between high pole count and simultaneous force generation capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system dynamically configures the winding strands based on operational requirements. The strands can be individually controlled or reconfigured between star and ring connections, enabling the system to adapt between torque-dominated and lateral force-dominated modes while maintaining high power density from the increased pole count

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If sensors are added to control torque and transverse force generation, then control precision is improved, but power density is reduced and device complexity increases

Engineering Contradiction:
Improvecontrol precisionVSAvoidpower density
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The segmented winding strands serve multiple functions: they can be individually controlled for precise torque and lateral force generation, and they can be reconfigured between star and ring connections to adapt to different operational modes. This multi-functionality reduces the need for additional sensors and control components, maintaining power density while achieving precise control

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If complex coil arrangements are used to generate both torque and transverse forces, then force generation capability is improved, but device complexity and production costs increase

Engineering Contradiction:
Improveforce generation capabilityVSAvoidcoil arrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The coil arrangement is segmented into at least four independent winding strands that can be individually controlled. This segmentation simplifies the control logic compared to complex multi-phase systems, as each strand can be independently activated or combined in star/ring configurations to achieve the desired force generation capability with reduced overall system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes its operational parameters by reconfiguring the winding strands between star and ring connections based on the required force generation mode. This parameter change approach allows the same physical coil arrangement to provide different force generation capabilities without requiring physically complex reconfigurable structures, thereby reducing device complexity while maintaining versatility

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

This design achieves high power density and efficient force generation at low speeds with reduced complexity and production costs, while also simplifying the integration of sensors and magnetic bearings, enhancing energy efficiency and motor utilization.

Implementation Method 1

at least four different winding phases of a stator winding, these winding phases interact with at least one permanent magnet of the rotor for the simultaneous formation of a torque and a transverse force

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Implementation Method 2

the invention further proposes that, in the case of at least one winding strand, its coils be arranged within a stator division of 360 degrees divided by the number of winding strands. For this purpose, the winding strands or motor strands can be controlled individually or preferably connected in a star or ring for further structural simplicity-comparatively simple control electronics being able to suffice for the star or ring connection. The above-mentioned arrangement of the winding strands in the stator division according to the invention can also result in a particularly efficient generation of force due to the main use of radial components of the Maxwell forces

Methodology Applied
Scientific EffectMaxwell forces: Lorentz Force

Data Source

PatentEP2587636B1Electrical machine, in particular brushless torque motor
Publication Date: 2019.01.16 LINZ CENT OF MECHATRONICS
  • EP2587636B1 patent drawingFigure 1
  • EP2587636B1 patent drawingFigure 2
  • EP2587636B1 patent drawingFigure 3

AI summary

The machine (1) has a stator (3) including an electromagnetically conductive stator yoke (5) and four different winding strands (6-9) i.e. groove-less air gap windings, of a stator winding (2) i.e. two-layered toothed coil winding, where the strands cooperate with permanent magnets (11) of a rotor (10) e.g. inner rotor. Each strand includes coils (6'-9', 6''-9''), which are electrically connected with each other. The coils are arranged in the winding strands within a stator division (14), which is determined by dividing three hundred and sixty degrees by a number of the winding strands.