BLDC Motor Controller Eliminates Slip Rings for Propeller Power

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Solution Overview

Problem

Existing aircraft propeller systems face challenges with high weight, cost, and complexity due to the need for slip rings or hydraulic power transmission to transfer power and control signals between the static and rotating components, particularly in adapting to electric propulsion mechanisms.

Innovation Solution

A brushless DC electric motor system with a rotor and stator configuration that eliminates the need for slip rings by using a motor controller to apply transient and static DC voltages, allowing direct drive of propellers and integration of variable pitch and deicing systems, reducing weight and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If slip rings or hydraulic power transmission are used to transfer power and control signals between static and rotating components, then power transmission is achieved, but weight and device complexity increase

Engineering Contradiction:
Improvepower transmissionVSAvoidweight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent extracts the power transmission function from the rotating propeller system by using the BLDC motor's stator windings to generate power directly on the rotating side. This eliminates the need for slip rings and hydraulic power transmission lines that would otherwise be required to transfer power from the static side to the rotating propeller.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The BLDC motor system performs multiple functions: it drives the propeller rotation while simultaneously generating electrical power through its alternator windings. This multi-functionality eliminates the need for separate power transmission systems, reducing both weight and complexity.

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

2Power

If slip rings or hydraulic power transmission are used to transfer power and control signals between static and rotating components, then power transmission is achieved, but device complexity increases

Engineering Contradiction:
Improvepower transmissionVSAvoiddevice complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges the power transmission function with the motor control system by using the same BLDC motor controller to manage both propeller drive and power generation. The controller applies different voltage patterns to the stator windings depending on whether the system is in motor mode or generator mode, eliminating the need for separate power transmission mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent removes the complex slip ring and hydraulic power transmission infrastructure by extracting the power generation function directly into the rotating BLDC motor system. This eliminates multiple separate systems and their associated complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If additional power transmission lines are installed to power variable pitch and deicing systems on the rotating propeller, then functional requirements are met, but weight increases

Engineering Contradiction:
Improvefunctional capabilityVSAvoidweight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The BLDC motor system serves itself by generating its own electrical power through the alternator windings on the rotating side. This self-generated power is used to drive the variable pitch mechanism and deicing systems, eliminating the need for additional power transmission lines from the static side.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The BLDC motor system provides universal power supply for all rotating components including propeller rotation, variable pitch control, and deicing systems. This single integrated power source eliminates the need for multiple separate power transmission lines.

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

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 power transfer and control without the need for additional power transmission lines, reducing weight, cost, and complexity, while allowing for direct drive and integration of electrically powered systems on the propeller engine.

Implementation Method 1

passing the current through one or more windings that each generate a magnetic field. One or more permanent magnets are used to produce one or more secondary magnetic fields, and a reciprocating force is generated in between the windings on one side and the magnets on the other due to the interaction between the magnetic fields.

Methodology Applied
Scientific EffectMagnetic field interaction: Lorentz Force

Implementation Method 2

The stationary windings can be configured to move the permanent magnets (and the rotor) by being energised in a controlled sequence to produce a rotating magnetic field

Methodology Applied
Scientific EffectRotating magnetic field: Electromagnetic Induction

Implementation Method 3

The controller is configured to apply a first, transient DC voltage to the windings of the stator, wherein the first, transient DC voltage is configured to provide commutation switching for the windings of the stator so as to generate a torque on the rotor via the permanent magnets.

Methodology Applied
Scientific EffectElectromagnetic torque generation: Lorentz Force

Implementation Method 4

The controller is further configured to apply a second, static DC voltage to the windings of the stator, wherein the second, static DC voltage is configured to induce an electric current in the alternator windings so as to generate an AC voltage in the alternator windings.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3792177B1System comprising a brushless direct current electric motor for a propeller engine
Publication Date: 2022.08.03 RATIER FIGEAC SAS
  • EP3792177B1 patent drawingFigure 1
  • EP3792177B1 patent drawingFigure 2
  • EP3792177B1 patent drawingFigure 3

AI summary

There is provided a system comprising a brushless DC ("BLDC") electric motor for a propeller engine and a motor controller. The motor comprises a rotor including one or more permanent magnets and one or more alternator windings, and a stator including one or more stator windings. The controller is configured to apply a first, transient DC voltage to the windings of the stator, wherein the first, transient DC voltage is configured to provide commutation switching for the windings of the stator so as to generate a torque on the rotor. The controller is further configured to apply a second, static DC voltage to the windings of the stator, wherein the second, static DC voltage is configured to induce an electric current in the alternator windings so as to generate an AC voltage in the alternator windings.