External Modulation for ISVF Generator Rotor

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Solution Overview

Problem

Independent speed variable frequency (ISVF) generators face challenges due to the inclusion of modulation circuitry on the rotor, which increases costs and reduces the lifespan of electrical components, and strong rotational forces affect the longevity of these components.

Innovation Solution

The ISVF generator system performs modulation functions externally to the rotor, generating a high-frequency modulated multiphase power signal that is transmitted to the rotor to drive the main machine stage, eliminating the need for modulation circuitry on the rotor and reducing exposure to rotational forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If modulation circuitry is included on the rotor to achieve independent frequency control, then independent speed variable frequency capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveindependent frequency controlVSAvoidmodulation circuitry on rotor
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the modulation circuitry from the rotor and relocates it to the stator. The stator-based modulation circuitry generates a modulated power signal that is transmitted to the rotor through slip rings, achieving independent frequency control without the complexity and cost of having modulation circuitry directly on the rotor.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces slip rings as an intermediary mechanism to transmit power from the stator to the rotor. This allows the modulation circuitry to remain on the stator while still enabling independent frequency control of the rotor, resolving the contradiction between adaptability and device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If modulation circuitry is included on the rotor to achieve independent frequency control, then independent speed variable frequency capability is improved, but manufacturing cost increases

Engineering Contradiction:
Improveindependent frequency controlVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent extracts the modulation circuitry from the rotor and relocates it to the stator, significantly reducing manufacturing cost. The stator-based modulation circuitry is easier and less expensive to manufacture than rotor-mounted circuitry, while still achieving independent frequency control through the modulated power signal transmitted via slip rings.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If electrical components are placed on the rotor for modulation, then independent frequency control is achieved, but component lifespan decreases due to strong rotational forces

Engineering Contradiction:
Improveindependent frequency controlVSAvoidcomponent lifespan
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts all modulation circuitry from the rotor and places it on the stator, eliminating the reliability issues associated with rotational forces affecting electrical components. The slip rings serve as a reliable transmission medium, allowing the rotor to remain free of fragile electrical components while maintaining independent frequency control capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The slip rings act as an intermediary that reliably transmits the modulated power signal from the stator to the rotor, enabling independent frequency control without placing electrical components on the rotor. This resolves the contradiction between adaptability and reliability by using a simple, robust mechanical connection.

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 approach extends the lifespan of rotor components, reduces complexity, and maintains independent frequency control of the generated power signal, enhancing the system's efficiency and reliability.

Implementation Method 1

a pilot generator stage including a magnetic field source positioned on the rotor and a set of pilot multiphase windings positioned on the stator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a high frequency transformer stage including a first set of high frequency transformer multiphase windings positioned on the stator and a second set of high frequency transformer multiphase windings positioned on the rotor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

applying the main field multiphase power signal component to a set of main field multiphase windings positioned on the rotor to generate an asynchronous rotating magnetic flux

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

converting the asynchronous rotating magnetic flux into a main machine multiphase power signal at a set of main armature multiphase windings positioned on the stator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3562028B1Externally modulated independent speed variable frequency generator
Publication Date: 2020.09.23 THE BOEING CO
  • EP3562028B1 patent drawingFigure 1
  • EP3562028B1 patent drawingFigure 2
  • EP3562028B1 patent drawingFigure 3

AI summary

Described is an independent speed variable frequency generator system that may include a rotor and a stator. The system may further include a pilot generator stage including a magnetic field source positioned on the rotor and a set of pilot multiphase windings positioned on the stator. The system may also include a high frequency transformer stage including a first set of high frequency transformer multiphase windings positioned on the stator and a second set of high frequency transformer multiphase windings positioned on the rotor. The system may also include a main machine stage including a set of main field multiphase windings positioned on the rotor and a set of main armature multiphase windings positioned on the stator, where the second set of high frequency transformer multiphase windings are coupled directly to the set of main field multiphase windings. The system may include a generator control unit.