Hybrid Engine Fly-Mode Control for Generator Load Drop Overspeed
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Solution Overview
Problem
Hybrid drones using turboshaft engines face overspeeding issues due to rapid generator load reductions, which can lead to engine damage, as existing control systems react too late to prevent over-rotation.
Innovation Solution
A hybrid engine system with a controller that measures torque and current reduction rates to proactively change control modes to stop, idle, or increase deceleration rates, preventing overspeeding by anticipating generator load changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a turboshaft engine is used in a hybrid drone system, then the engine provides stable power output, but the engine is vulnerable to overspeeding when generator load rapidly decreases
Solution Approach 1:
The controller performs preliminary detection of rapid load reduction by monitoring torque and current reduction rates, and proactively switches to a stop mode before overspeeding occurs. This anticipatory action prevents the harmful effect by acting in advance rather than reacting after overspeeding begins.
Solution Approach 2:
The invention converts the potentially harmful rapid load reduction into a beneficial control opportunity by detecting it through torque and current monitoring, then utilizing this information to switch to stop mode, thereby protecting the engine while maintaining system responsiveness.
2Power
If the engine operates in fly mode during rapid generator load reduction, then power output is maintained, but the engine controller exceeds its control limit and cannot prevent overspeeding
Solution Approach 1:
The controller dynamically switches between fly mode and stop mode based on real-time monitoring of torque and current reduction rates. This dynamic adaptation allows the system to maintain power output during normal operation while automatically transitioning to stop mode when rapid load reduction is detected, ensuring control effectiveness is preserved.
Solution Approach 2:
The controller continuously monitors torque and current as feedback signals, compares their reduction rates against thresholds, and adjusts the engine mode accordingly. This feedback mechanism enables the controller to detect rapid load reductions and respond by switching to stop mode, maintaining control effectiveness throughout operation.
3Reliability
If the engine is stopped to prevent overspeeding, then engine safety is protected, but flight continuity is interrupted
Solution Approach 1:
The controller applies preliminary anti-action by detecting rapid load reduction through torque and current monitoring and switching to stop mode before overspeeding occurs. This preventive measure protects engine safety while minimizing flight interruption by acting only when necessary rather than continuously stopping.
Solution Approach 2:
The controller changes the operational parameter of the engine from fly mode to stop mode based on detected torque and current reduction rates. This parameter change enables the system to balance engine safety protection with flight continuity by transitioning modes only when rapid load reduction is detected, rather than maintaining a fixed state.
Data Source
AI summary
A hybrid engine system includes: an engine; a generator driven by the engine to output electrical energy; a battery configured to store electrical energy produced by the generator or supply electrical energy together with the generator; and a controller configured to control the engine, wherein the controller includes a torque meter for measuring torque of an output shaft of the engine and a current meter for measuring output current of the generator, and is further configured to change a control mode of the engine when a reduction rate of at least one of the torque and the current is greater than a set value while the engine is operating in a fly mode.