Electric Propulsion Feed-Forward Control for Transient Power Demand
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Solution Overview
Problem
Conventional electric propulsion systems for aircraft face limitations in dynamic response and efficiency due to the latency in feedback mechanisms, leading to increased weight and cost from oversized generators needed to handle transient power demands, which restricts their implementation in weight-critical applications.
Innovation Solution
An electric propulsion system with an integrated generator-motor controller that uses a feed-forward mechanism to anticipate and manage power demands, allowing for a generator capable of lower peak current usage, thereby reducing weight and cost, and enhancing dynamic response by matching the bandwidth of the generator and prime mover with the electric motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional feedback mechanism is used to control generator output voltage, then the generator can maintain stable voltage within tolerance, but the dynamic response is delayed due to inherent latency in the feedback loop
Solution Approach 1:
The patent applies preliminary action by using a feed-forward control mechanism that anticipates power demand changes before they occur. The controller receives a power demand parameter associated with the control signal and uses it to proactively adjust generator field current, eliminating the latency inherent in conventional feedback loops that only react after voltage deviations are detected.
2Power
If the generator is oversized to handle transient power demands, then the system can meet peak power requirements, but the weight and cost of the system increase
Solution Approach 1:
The feed-forward control mechanism enables the generator to be properly sized for steady-state operation by anticipating transient power demands. The controller uses the power demand parameter to proactively adjust field current before transients occur, allowing a smaller, lighter generator to meet both steady-state and transient requirements without requiring oversizing for peak conditions.
3Adaptability or versatility
If the prime mover speed is varied to match propulsion requirements, then the system can adapt to changing power demands, but the prime mover operates inefficiently when not at optimal speed
Solution Approach 1:
The patent applies feedback by using the power demand parameter from the control signal to adjust generator field current, enabling the prime mover to operate at constant optimal speed while the generator adapts to varying power demands. This decouples the prime mover speed from propulsion power requirements, maintaining prime mover efficiency while providing system adaptability through electrical control.
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 feed-forward control system improves the dynamic response and stability of the propulsion system, enabling more efficient power delivery and reducing the weight and cost of the system, particularly beneficial in aerospace applications by allowing for more dynamic control of propulsion forces.
Implementation Method 1
an electric generator arranged to be driven by the prime mover to generate electric power
Implementation Method 2
an electric propulsion motor; and an integrated generator-motor controller arranged to control the supply of said electric power to the electric propulsion motor
Data Source
AI summary
An electric propulsion system is provided which includes a prime mover; an electric generator which is arranged to be driven by the prime mover to generate electric power; an electric propulsion motor; and an integrated generator-motor controller arranged to control the supply of said electric power to the electric propulsion motor in response to a control signal. The integrated generator-motor controller is also arranged to feed-forward to the generator a power demand parameter associated with the control signal so as to control the power output of the generator.