Aircraft Propeller Control Under Supply Voltage Drop
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Solution Overview
Problem
Existing monitoring systems for electric thrusters in aircraft fail to maintain optimal torque and thrust when supply voltage drops below a certain threshold, leading to potential stall and loss of lift or thrust, especially when multiple motors with different voltage sources are used.
Innovation Solution
A monitoring device that measures supply voltage and adjusts the speed of rotation and pitch of the propeller to maintain a constant torque and thrust by using inverters and pitch control, optimizing the speed of rotation based on the lowest supply voltage across multiple motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the supply voltage drops below the CEMF threshold, then the motor cannot maintain its speed of rotation, but maintaining torque requires voltage higher than CEMF
Solution Approach 1:
The patent applies dynamics by making the speed of rotation adjustable and adaptive rather than fixed. The control device dynamically modifies the speed of rotation based on the relationship between supply voltage and CEMF, allowing the motor to operate at reduced speeds when voltage drops, thereby maintaining positive torque throughout the operating range
Solution Approach 2:
The patent changes the operating parameters by allowing speed of rotation to vary as a control variable. By adjusting speed based on voltage conditions, the system maintains the fundamental motor operation principle (supply voltage > CEMF) while adapting to varying voltage levels, thus preserving torque capability
2Speed
If multiple motors with different voltage sources drive the same propeller, then the motor with highest supply voltage imposes the speed, but the motor with lowest supply voltage cannot follow and stalls
Solution Approach 1:
The patent implements feedback by continuously monitoring the supply voltage of each motor and using this information to adjust the speed of rotation. The control device receives voltage information from multiple motors and modifies the operating speed to ensure all motors can operate reliably without stalling
Solution Approach 2:
The system dynamically adapts the speed of rotation based on the voltage conditions of all connected motors. Rather than imposing a fixed speed from the highest voltage motor, the system continuously adjusts speed to match the capabilities of all motors, ensuring reliable operation of the entire multi-motor system
3Reliability
If the motor limits torque or speed when supply voltage is too low, then the motor avoids operating below CEMF, but the aircraft loses lift or thrust
Solution Approach 1:
The patent changes the speed parameter to compensate for voltage drops. By reducing speed appropriately when voltage decreases, the system maintains the voltage>CEMF condition for reliable motor operation while minimizing the impact on mechanical power output, thus preserving aircraft performance
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
The device ensures continuous power delivery by maintaining a constant torque and thrust, preventing sudden drops in mechanical power and ensuring safe operation of the aircraft by adapting to varying supply voltages.
Implementation Method 1
an electric machine produces a voltage called electromotive force (EMF) voltage when it is speed-driven. This voltage is proportional to the speed of rotation. In the case of an operation of the electric machine as a motor, this EMF is also produced but opposes the supply current of the motor. It is then called 'counter-electromotive force' (CEMF).
Data Source
AI summary
The present invention relates to a device (1) for controlling an electric aircraft-propelling assembly, said propelling assembly comprising a propeller (3) and at least one electric motor (4) that is powered by an electric supply voltage and that delivers a torque and a rotation speed to drive the propeller (3). The control device (1) comprises at least a unit (11) for measuring an electric supply voltage, and a control unit (12) suitable for making a signal delivered to the electric motor vary as a function of said electric supply voltage, with a view to making the rotation speed of the propeller vary.