Hybrid Aircraft Generator-Propulsor Frequency Synchronization
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Solution Overview
Problem
Existing hybrid electric aircraft propulsion systems face challenges in efficiently synchronizing the frequency between generators and electric propulsors, leading to desynchronization issues that affect propulsion efficiency and reliability.
Innovation Solution
The method involves disconnecting and reconnecting the generator from the electric propulsors, using motor inverters to synchronize frequencies, and modulating AC electric power to maintain connection during synchronization, with a controller managing these processes to prevent and recover from desynchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the generator is continuously connected to the electric propulsors during operation, then power delivery is maintained, but desynchronization between generator and propulsor frequencies occurs leading to propulsion inefficiency
Solution Approach 1:
The system performs preliminary disconnection of the generator from the propulsor before frequency changes are needed, allowing independent frequency adjustment without synchronization conflicts. The controller detects frequency differences and temporarily disconnects the generator connection to enable safe frequency modulation of the propulsor motors.
Solution Approach 2:
The system dynamically switches between connected and disconnected states of the generator-propsor link based on operational requirements. The controller continuously monitors frequency and dynamically controls the connection state, transitioning from connected (for power delivery) to disconnected (for frequency adjustment) and back again.
2Reliability
If the generator frequency is changed to match propulsor frequency requirements, then synchronization is achieved, but the process causes interruptions in power delivery
Solution Approach 1:
The system performs preliminary disconnection before frequency changes, allowing the propulsor frequency to be adjusted to match the generator frequency without attempting to change generator frequency under load, which would cause instability and interruptions.
3Adaptability or versatility
If the generator and propulsor operate at different frequencies, then operational flexibility is maintained, but desynchronization occurs leading to system failure
Solution Approach 1:
The system dynamically adjusts its operational mode based on frequency matching requirements. When frequency mismatch is detected, the controller transitions to a disconnected state where the propulsor can operate independently at its optimal frequency. When synchronization is achieved, the system transitions to a connected state for efficient power delivery, thus maintaining both flexibility and stability.
Solution Approach 2:
The controller continuously monitors the frequency of both the generator and propulsor motors, providing feedback that triggers connection state changes. When frequency difference exceeds a threshold, the controller initiates disconnection; when frequencies match, the controller initiates reconnection, creating a closed-loop control system that maintains reliability while allowing operational flexibility.
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 approach enhances propulsion system efficiency by maintaining synchronization, ensuring reliable power delivery and reducing the risk of desynchronization, thereby improving overall aircraft performance.
Implementation Method 1
The generator is connected to the combustion engine and is selective capable of providing AC electric power to the electric propulsors
Implementation Method 2
The electric propulsors are connected to motor inverters and are selective capable of receiving AC electric power from the generator or from an external ground power unit
Data Source
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AI summary
A method and system (200) for operating a hybrid electric aircraft propulsion system. The method comprises modulating AC electric power applied to a first electric propulsor (206A) or a second electric propulsor (206B) from at least one motor inverter (208A,208B;308) to synchronize the frequency of the first electric propulsor (206A) or the second electric propulsor (206B) with the frequency of a generator (202).