Brushless Claw Pole Synchronous Machine Design

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Solution Overview

Problem

Conventional claw pole synchronous machines have increased weight, volume, and complexity due to the need for excitation windings and cooling systems to manage heat generated by the excitation field, as well as frequent maintenance requirements.

Innovation Solution

A brushless claw pole synchronous machine design that eliminates the internal excitation winding by using ring-shaped DC excitation coils and a ferromagnetic housing with magnetization flux paths to generate a magnetic field, reducing the need for additional components and heat management systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional excitation windings are used in the rotor, then the magnetic field can be generated, but the weight, volume, and complexity of the machine increase

Engineering Contradiction:
Improvemagnetic field generationVSAvoidrotor weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The excitation winding is extracted from the rotor and relocated to the stator. The rotor is made devoid of coils and permanent magnets, containing only the爪 poles. The excitation coils are now part of the stator assembly, which eliminates the need for slip rings, brushes, and complex cooling systems in the rotating part, thereby reducing rotor weight and simplifying the overall structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A ferromagnetic housing with magnetization flux paths serves as an intermediary to transfer the magnetic field from the stator excitation coils to the rotor爪 poles. The flux paths in the housing guide the magnetic flux through the rotor without requiring windings inside the rotor, achieving magnetic field generation while maintaining a simple rotor structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If excitation windings are placed in the rotor, then the magnetic field is created, but the device complexity and maintenance requirements increase

Engineering Contradiction:
Improvemagnetic field generationVSAvoidstructure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The excitation winding is extracted from the rotor and relocated to the stator. The rotor is made devoid of coils and permanent magnets, containing only the爪 poles. The excitation coils are now part of the stator assembly, which eliminates the need for slip rings, brushes, and complex cooling systems in the rotating part, thereby reducing rotor weight and simplifying the overall structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The excitation coils are merged with the stator assembly, and the ferromagnetic housing with flux paths is integrated to provide both structural support and magnetic flux guidance. This consolidation eliminates the need for separate rotor windings, slip rings, and external cooling systems, reducing the overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Power

If internal excitation windings are used, then the magnetic field can be generated, but heat management systems are required

Engineering Contradiction:
Improvemagnetic field generationVSAvoidheat management
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The excitation winding is extracted from the rotor and relocated to the stator. The rotor is made devoid of coils and permanent magnets, containing only the爪 poles. The excitation coils are now part of the stator assembly, which eliminates the need for slip rings, brushes, and complex cooling systems in the rotating part, thereby reducing rotor weight and simplifying the overall structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical cooling system required for rotor windings is replaced by utilizing the stator's existing cooling infrastructure. The ferromagnetic housing with flux paths provides a passive thermal management solution by conducting heat away from the excitation coils in the stator, eliminating the need for active cooling systems in the rotor.

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

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 simplifies the machine, reduces weight and volume, and minimizes maintenance needs while maintaining efficient power generation and motor operation by leveraging the ferromagnetic housing and DC excitation coils to create a magnetic field without internal windings or permanent magnets.

Implementation Method 1

a ferromagnetic housing including a radially outward cylindrical yoke connecting two axially opposite ferromagnetic end bells, and wherein each excitation flux path surrounding, and interfacing with, a corresponding one of the at least two DC excitation coils allowing the DC excitation coil to magnetize a corresponding rotor disk

Methodology Applied
Scientific EffectMagnetic flux path: Magnetic Field

Implementation Method 2

The rotor includes two ferromagnetic rotor disks with interfaced ferromagnetic claw poles

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

rotation of the rotor generates electricity due to interaction of a generated rotating magnetic field and a stator winding exterior to the rotor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3442102B1Claw pole brushless synchronous machine
Publication Date: 2022.09.28 HAMILTON SUNDSTRAND CORP
  • EP3442102B1 patent drawingFigure 1
  • EP3442102B1 patent drawingFigure 2~3

AI summary

A claw pole synchronous machine includes a housing (240) and a rotor (100) being rotatable relative to the housing and having a plurality of first claw poles (130) circumferentially alternating with a plurality of second claw poles. The plurality of first claw poles are axially overlapping with the plurality of second claw poles. At least two DC excitation coils (210) are fixed relative to the housing and configured to provide a magnetic field to the rotor. A stator is fixed to the housing.