Variable Frequency AC Generator with Rotor Inverter

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Solution Overview

Problem

Aircraft systems face inefficiencies and weight increases due to the need for two stages of power conversion to generate independent or variable frequency AC power, which decreases efficiency and adds significant weight.

Innovation Solution

An independent speed variable frequency AC generator apparatus with a rotor and stator, where the rotational frequency of a rotating magnetic field is independent of the rotor's rotational frequency, using a magnetic field source, main rotor winding, and control circuitry to generate and modulate AC power signals, eliminating the need for contact power transmission mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two stages of power conversion are used to generate independent frequency AC power, then frequency independence is achieved, but system weight increases significantly

Engineering Contradiction:

Improvefrequency independenceVSAvoidsystem weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent combines the power conversion and frequency conversion functions into a single integrated generator system. The rotor-mounted inverter directly modulates the magnetic field frequency to produce independent frequency AC power, eliminating the need for separate converter stages and reducing overall system weight.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The generator system performs multiple functions simultaneously: it generates electrical power while independently controlling output frequency through the rotor-mounted inverter. This multi-functionality eliminates the need for dedicated frequency conversion equipment, reducing system weight and complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If two stages of power conversion are used to generate independent frequency AC power, then frequency independence is achieved, but system efficiency decreases

Engineering Contradiction:

Improvefrequency independenceVSAvoidpower conversion efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

By merging the power generation and frequency conversion operations into a single integrated system, the patent eliminates intermediate conversion stages. The rotor-mounted inverter directly controls the magnetic field frequency, reducing energy losses that would occur in separate converter stages.

Inventive Principle:

Principle #5Merging (Combining)

3Power

If contact power transmission mechanisms are used in the generator, then power transmission is achieved, but maintenance costs increase and power losses occur

Engineering Contradiction:

Improvepower transmissionVSAvoidmaintenance costs

Core Design Contradiction:

PowerVSEase of repair

Solution Approach 1:

The patent replaces mechanical contact-based power transmission with a contactless electromagnetic coupling system. The rotor-mounted inverter generates the magnetic field that directly induces power in the stator windings, eliminating brushes, commutators, and other contact components that require maintenance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Power

If contact power transmission mechanisms are used in the generator, then power transmission is achieved, but power losses increase

Engineering Contradiction:

Improvepower transmissionVSAvoidpower losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent replaces mechanical contact-based power transmission with a contactless electromagnetic coupling system. The rotor-mounted inverter generates the magnetic field that directly induces power in the stator windings, eliminating contact resistance, arcing, and friction losses associated with traditional contact mechanisms.

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 solution enables efficient, lightweight AC power generation with independent frequency and phase, reducing maintenance costs and power losses by eliminating contact mechanisms, and allowing for reliable operation with fewer power conversion stages.

Implementation Method 1

a magnetic field source attached to the rotor and configured to generate a first rotating magnetic field upon rotation of the rotor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a main rotor winding attached to the rotor and configured to generate a second rotating magnetic field upon the rotation of the rotor, where a rotational frequency of the second rotating magnetic field is independent of the rotational frequency of the rotor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a pilot winding attached to the stator and configured to convert the first rotating magnetic field into an AC power signal

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3487063B1Independent speed variable frequency alternating current generator

Publication Date: 2021.01.06 THE BOEING CO

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AI summary

An independent speed variable frequency alternating current (AC) generator apparatus may include a rotor and a stator, the rotor configured to rotate relative to the stator. The apparatus may further include a magnetic field source attached to the rotor and configured to generate a first rotating magnetic field upon rotation of the rotor, where a rotational frequency of the first rotating magnetic field is dependent on a rotational frequency of the rotor. The apparatus may also include a main rotor winding attached to the rotor and configured to generate a second rotating magnetic field upon the rotation of the rotor, where a rotational frequency of the second rotating magnetic field is independent of the rotational frequency of the rotor.