Dual-Rotor Electric Machine Harmonic Control
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Solution Overview
Problem
Current electric aircraft propulsion systems require dual-rotor electric machines with high torque and power density to improve performance, but existing designs struggle to efficiently manage different rotational speeds and directions of dual rotors with a single signal converter.
Innovation Solution
A dual-rotor electric machine design featuring a stator with slots and windings, where one rotor interacts with the stator via a fundamental armature field spatial harmonic and the other via a higher-order harmonic, using permanent magnetic materials and differing magnetic pole pairs to achieve simultaneous rotation at different speeds and directions, allowing for control with a single signal converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If different numbers of magnetic pole pairs are used on the first and second rotors to interact with different spatial harmonics, then torque and power density are improved, but control system complexity increases
Solution Approach 1:
The single signal converter is designed to perform multiple functions by controlling both the first and second rotors simultaneously. It generates different control signals for each rotor to achieve independent speed and direction control, thereby managing the complexity that would otherwise require separate converters for each rotor while maintaining the ability to exploit different spatial harmonics for enhanced power density
2Productivity
If the first rotor rotates at a different speed and in the opposite direction to the second rotor, then propulsion performance is improved, but synchronization control difficulty increases
Solution Approach 1:
The control system dynamically adjusts the rotational speeds and directions of the first and second rotors independently through a single signal converter. This allows the rotors to operate at optimized speeds for their respective spatial harmonics while maintaining coordinated control, enabling improved propulsion performance without requiring fixed mechanical synchronization
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 enhances torque and power density while simplifying control by using different magnetic field spatial harmonics, enabling efficient power transmission and propulsion in electric aircraft systems.
Implementation Method 1
a first rotor arranged to rotate relative to the stator with an insulating gap therebetween, the first rotor comprising a first rotor excitation element having one or more magnetic pole pairs arranged to interact with the stator windings
Implementation Method 2
The first rotor excitation element may be arranged to interact with the stator windings via a first rotor magnetic field in the insulating gap between the first rotor and the stator
Implementation Method 3
one or both of the first and second rotor excitation elements comprises a permanent magnetic material
Data Source
AI summary
The dual rotor electric machine comprises: a stator having one or more slots and one or more stator windings. The dual rotor electric machine further comprises a first rotor arranged to rotate relative to the stator with an airgap therebetween. The first rotor comprises a first rotor excitation element having one or more magnetic pole pairs arranged to interact with the stator windings, the first rotor configured to rotate about an axis (X). The dual rotor electric machine further comprises a second rotor arranged to rotate relative to the stator with an airgap therebetween. The second rotor comprises a second rotor excitation element having one or more magnetic pole pairs arranged to interact with the stator windings, the second rotor being configured to rotate about the axis (X).