Voltage Regulated Permanent Magnet Generator Stator Control Winding

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Solution Overview

Problem

Existing voltage regulated generators in aircraft require complex and costly designs to control output voltage without adjusting rotor speed, as they rely on magnetic shims, complex windings, or housing the stator within the rotor, which increases assembly complexity and maintenance costs.

Innovation Solution

A single phase permanent magnet generator with a stator exterior to the rotor, featuring an armature winding and a control winding acting as a magnetic flux diverter, where a controller adjusts the magnetic permeability of the control winding to regulate output voltage by creating an alternate magnetic flux path, affecting the induced electromagnetic field of the armature winding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetic shims are used in the rotor to control voltage output, then voltage regulation is achieved, but the device complexity and manufacturing cost increase due to high-speed physical shifting mechanisms

Engineering Contradiction:
Improvevoltage regulationVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the voltage control function from the rotor to the stator by introducing a control winding on the stator core. This separates the rotational function (permanent magnets on rotor) from the control function (electromagnetic flux diversion on stator), eliminating the need for complex moving magnetic shims while achieving the same voltage regulation effect.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical magnetic shim shifting system with an electromagnetic control system. Instead of physically moving magnetic shims at high speeds, the invention uses electromagnetic induction through the control winding to dynamically adjust magnetic flux distribution, substituting mechanical motion with electromagnetic field control.

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

2Reliability

If complex windings with multiple sections are used to control voltage at different rotor speeds, then voltage regulation across speed ranges is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvevoltage regulation across speed rangesVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces a dynamic control mechanism where the control winding's magnetic permeability can be adjusted in real-time based on rotor speed and load conditions. This dynamic adjustment allows a single, simple winding design to adapt to varying operating conditions, replacing the need for multiple fixed winding sections with different activation ranges.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the magnetic permeability parameter of the control winding dynamically to achieve voltage regulation. By controlling the magnetic permeability of the stator core through the control winding, the system can adjust voltage output across different rotor speeds without requiring complex multi-section windings, simplifying manufacturing while maintaining regulatory capability.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If DC current is used to saturate the armature winding for voltage control, then voltage regulation is achieved, but the device complexity and maintenance requirements increase

Engineering Contradiction:
Improvevoltage controlVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent introduces a control winding on the stator as an intermediary element that indirectly controls the magnetic flux reaching the armature winding. Instead of directly saturating the armature with DC current, the control winding modulates the magnetic field before it reaches the armature, reducing stress on the armature winding and simplifying maintenance requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If the stator is housed within the rotor with complex control and armature windings, then voltage regulation is achieved, but the device complexity and assembly difficulty increase

Engineering Contradiction:
Improvevoltage regulationVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional arrangement by placing the control winding on the stator rather than housing the stator within the rotor. This reversal simplifies the structural arrangement, allowing the rotor to focus solely on rotation with permanent magnets while the stator handles both armature and control windings, significantly reducing assembly complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

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 allows for efficient voltage regulation without altering rotor speed, reducing complexity and cost by using a simple winding design and external controller to manage magnetic permeability, thereby maintaining voltage within specified limits across varying loads and turbine engine speeds.

Implementation Method 1

a control winding on a second of said two core sections; a controller configured to receive a value representative of a rotor speed, determine a desired magnetic permeability of said control winding based on said measurement, and induce a current in said control winding, thereby altering a magnetic permeability of an alternate magnetic flux flow path

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

said control winding is capable of acting as a magnetic flux diverter, thereby regulating an output voltage of said armature winding

Methodology Applied
Scientific EffectMagnetic flux diversion: Magnetic Field

Implementation Method 3

Vehicles, such as aircraft, typically employ multiple components which require electrical power to operate. Modem aircraft also contain generators which are capable of utilizing rotational energy from an aircraft turbine engine to turn a rotor and generate electricity.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2209190B1Voltage regulated permanent magnet generator
Publication Date: 2012.08.22 HAMILTON SUNDSTRAND CORP
  • EP2209190B1 patent drawingFigure 1
  • EP2209190B1 patent drawingFigure 2~4
  • EP2209190B1 patent drawingFigure 5~6b

AI summary

A single phase AC generator uses a rotor (202) contained within a stator (206). The stator has an armature winding (208) and a control winding (210) which is capable of having its magnetic permeability adjusted, thereby limiting the output voltage of the armature winding. The stator additionally has two core sections (302, 304).