Aircraft Propeller Motor Control Under Supply Voltage Drop
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Solution Overview
Problem
Existing electric propulsion systems in aircraft face issues with torque and thrust loss due to varying supply voltages, particularly when multiple motors are powered by different voltage sources, leading to potential stalling and loss of lift or thrust, exacerbated by the complexity of controlling permanent magnet synchronous machines.
Innovation Solution
A control device that measures supply voltage and adjusts the rotational speed and pitch of electric motors to maintain optimal torque and thrust by decoupling supply voltage from rotational speed, using inverters to modulate frequency and propeller pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the supply voltage to the electric motor decreases, then the rotational speed can be maintained, but the torque delivered by the motor decreases
Solution Approach 1:
The patent applies dynamics by making the motor control adaptive to changing supply voltage conditions. The control system dynamically adjusts operational parameters based on real-time voltage measurements, transitioning between different control modes (voltage-controlled at high voltage, speed-controlled at low voltage) to optimize performance under varying conditions.
Solution Approach 2:
The patent changes operational parameters (control mode, reference values) based on supply voltage levels. When voltage drops below a threshold, the system switches from voltage-controlled mode to speed-controlled mode, altering how the motor operates to maintain torque while accepting reduced speed capability.
2Power
If multiple motors with different supply voltages are used to drive the same propeller, then the system can operate with higher power sources, but the motor with the lowest voltage will stall
Solution Approach 1:
The patent implements feedback by continuously monitoring the supply voltage of each motor and using this information to adjust control parameters. The control system measures actual voltage levels and compares them to reference values, then modifies operational parameters accordingly to prevent any motor from stalling due to insufficient voltage.
Solution Approach 2:
The system dynamically adapts each motor's operation to its specific supply voltage conditions. Each motor operates in its optimal control mode based on its voltage level, with the control system continuously adjusting reference values and control strategies to maintain synchronized operation without stalling.
3Power
If the rotational speed is increased to meet power requirements, then the power consumption increases proportionally to the cube of the speed, accelerating battery discharge
Solution Approach 1:
The patent changes control parameters (voltage references, current limits) based on battery voltage levels. When battery voltage drops, the system adjusts operational parameters to reduce power consumption while maintaining acceptable performance, thereby extending battery discharge time and overall system duration.
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
Maintains consistent mechanical power delivery by preventing sudden torque drops, ensuring stable aircraft propulsion and control even with fluctuating battery voltages.
Implementation Method 1
The battery or generator provides the motor with a voltage and current supply. This voltage and current cause the motor to rotate and convert electrical energy into mechanical energy.
Implementation Method 2
an electrical machine produces a voltage called the electromotive force (EMF) voltage when it is driven by a rotating machine. This voltage is proportional to the rotational speed. When the electrical machine operates as a motor, this EMF is also produced but opposes the motor's supply current.
Data Source
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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.