Counter-Rotating Aircraft Propulsion Unit With Single-Motor Layout
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Solution Overview
Problem
Existing electric propulsion units for aircraft with vertical takeoff and landing capabilities face challenges due to large mass and footprint, which hinder propulsion efficiency and increase acoustic nuisances, particularly when integrating counter-rotating propulsion members and motors.
Innovation Solution
A compact electric propulsion unit design featuring a single electric motor with a peripheral stator element and two counter-rotating rotor elements, where the stator comprises offset phases to drive both rotors in opposite directions, reducing the need for complex control modules and central hubs, thus minimizing mass and footprint while optimizing airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate electric motors are integrated into a central hub to drive counter-rotating propulsion members, then the propulsion unit can achieve counter-rotation capability, but the hub diameter significantly increases, decreasing the air stream section and affecting propulsion efficiency
Solution Approach 1:
The patent merges two separate electric motors into a single electric motor with two independent stator windings. The first winding drives the first rotor in one direction while the second winding drives the second rotor in the opposite direction, eliminating the need for a large central hub and preserving air stream section.
Solution Approach 2:
The single electric motor performs multiple functions by using two independent stator windings that can independently control two rotors. This multi-functional design allows counter-rotation capability without requiring separate motor assemblies, thereby maintaining compact dimensions.
2Weight of stationary object
If electric motors are positioned outside the casing and connected by mechanical shafts, then the casing mass is reduced, but the overall assembly size and mass increase
Solution Approach 1:
The electric motor is nested within the peripheral casing, with the stator element mounted inside the casing and the rotor elements positioned within the air stream passage. This nested arrangement reduces overall assembly dimensions while maintaining lightweight casing design.
3Weight of moving object
If a single electric motor with shared phases is used to drive two counter-rotating propulsion members, then the mass and footprint are reduced, but complex phase sequencing control is required
Solution Approach 1:
The control system dynamically switches between different phase sequences to achieve different rotation directions. The same three phases can be arranged in different sequences (first sequence for one direction, second sequence for opposite direction), allowing flexible control without additional hardware complexity.
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 achieves high power density with reduced mass and footprint, enhancing propulsion efficiency and reducing acoustic disturbances by allowing counter-rotating propulsion members to straighten airflow without the need for complex synchronization of stator elements.
Implementation Method 1
a first rotor element, rigidly attached to the first propulsion member, configured to be magnetically driven by the first peripheral stage, a second rotor element, rigidly attached to the second propulsion member, configured to be magnetically driven by the second peripheral stage
Data Source
AI summary
The invention relates to an electric propulsion unit for an aircraft comprising at least one first propulsion member, a second propulsion member and a single electric motor configured to drive the first propulsion member and the second propulsion member in a counter-rotating manner, the electric motor comprising a peripheral stator element comprising a first peripheral stage and a second peripheral stage which are offset along an axis, the first peripheral stage comprising at least a first phase, a second phase and a third phase which are alternated according to a first sequence in such a way as to allow a rotation of the first rotor element in the first direction of rotation, the second peripheral stage comprising phases which are alternated according to a second sequence in such a way as to allow a counter-rotating rotation of the second rotor element.