Generator Regenerative Control to Prevent eVTOL Engine Stall
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Solution Overview
Problem
Existing power supply systems in electric vertical take-off and landing aircraft (eVTOL) face issues with engine stalling during engine start due to loss of generator assist torque after transistor cutoff, leading to unstable power generation.
Innovation Solution
A power supply system with a management controller that executes stall prevention control by setting engine and generator torque command values to maintain a regenerative state for the generator, ensuring continued engine rotation and preventing stalling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the transistor is cutoff to stop power supply from battery to generator, then power loss is reduced, but engine torque becomes insufficient causing engine stalling
Solution Approach 1:
The control method prepares the engine to operate independently before cutoff by ensuring it reaches a state where it can maintain rotation without generator assist torque. The controller monitors engine rotational speed and torque throughout the charging process, ensuring the engine is ready for cutoff without stalling.
Solution Approach 2:
The controller continuously monitors engine rotational speed and torque, and adjusts the cutoff timing based on real-time feedback. When the engine rotational speed decreases or torque becomes insufficient, the controller extends the charging period or adjusts cutoff timing to prevent engine stalling, creating a closed-loop control system.
2Reliability
If the charging period is extended to maintain engine rotational speed, then engine stalling is prevented, but power loss increases
Solution Approach 1:
The control method dynamically adjusts the charging period and cutoff timing based on real-time engine conditions. The controller monitors engine rotational speed and torque continuously, extending or shortening the charging period as needed to maintain engine stability while minimizing power loss, rather than using a fixed charging duration.
Solution Approach 2:
The controller changes operational parameters (cutoff timing, charging period duration) based on engine state. When engine torque is sufficient, cutoff occurs earlier to reduce power loss. When engine torque is insufficient, cutoff is delayed or the charging period is extended, optimizing the balance between preventing stalling and minimizing energy loss.
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 system effectively prevents engine stalling by maintaining generator assist torque, ensuring stable power generation and system reliability during engine start.
Implementation Method 1
a generator configured to generate electric power by being driven by the engine
Implementation Method 2
a power control unit configured to convert alternating current electric power output from the generator into direct current electric power
Implementation Method 3
the management controller executes stall prevention control for preventing the engine from stalling by setting the engine torque command value and the generator torque command value so as to bring the generator into a regenerative state
Data Source
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AI summary
In a power supply system (10), in a case where a target output electric power of a generator (16) that generates electric power by being driven by an engine (14) is 0 [kW], stall prevention control is executed in which an engine torque command value and a generator torque command value are determined so that the generator is brought into a regenerative state.