Hybrid Aircraft Propulsion Controller for Thrust Response
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Solution Overview
Problem
Hybrid electric aircraft face challenges in controlling the integration of gas turbine engines with electric propulsors due to differences in response speed, leading to inefficiencies and fuel savings issues, as the gas turbine engine takes longer to adjust to thrust demands compared to electric motors.
Innovation Solution
A controller system that manages the hybrid electric gas turbine system by determining an operational profile that minimizes fuel supply, electric power transfer, and thrust differences over time, balancing the operation of the electric motor, gas turbine, and storage unit to maintain optimal efficiency and reduce transient changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the gas turbine engine is used to drive the electric generator for power supply, then the system can achieve sustained electric power output, but the gas turbine takes longer to respond to thrust demand changes compared to the electric motor
Solution Approach 1:
The power supply is segmented into two sources: the electric storage unit for immediate response and the generator for sustained output. The controller divides the power demand between these two sources based on the operational phase, allowing the system to achieve both rapid response and sustained power capability.
Solution Approach 2:
The electric storage unit is pre-charged before operation to provide immediate power during transient phases. This preliminary energy storage allows the system to respond instantly to thrust demands before the slower gas turbine can ramp up its power output.
2Power
If the gas turbine operates at high power output, then sufficient thrust can be generated, but transient changes cause tip clearance variations that reduce operational efficiency
Solution Approach 1:
The controller continuously monitors the operational state of the gas turbine and adjusts the power demand in real-time. By providing feedback control, the system can maintain optimal tip clearance during transients, preventing energy losses while still achieving the required power output.
Solution Approach 2:
The controller dynamically adjusts the power demand on the gas turbine during transient phases, modulating the load to keep the turbine operating within efficient parameters. This dynamic control allows the system to achieve high power output when needed while minimizing energy losses during transitions.
3Loss of energy
If the controller optimizes for fuel efficiency by minimizing fuel supply to the gas turbine, then operational cost decreases, but the system may not meet rapid thrust demand changes
Solution Approach 1:
The electric storage unit acts as an intermediary between the pilot's thrust demand and the gas turbine. It absorbs the rapid transient power demands that would otherwise require the gas turbine to operate inefficiently, allowing the turbine to run at optimal fuel-efficient points while still meeting overall thrust requirements.
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 reduces transient changes and thermal transients in the gas turbine, maintaining tip clearance within a predetermined tolerance and optimizing fuel efficiency by balancing power supply from the electric storage unit and generator, ensuring efficient operation and reduced fuel consumption.
Implementation Method 1
a generator system, a propulsor, a controller and an electric storage unit, the generator system comprising an electric generator arranged to drive a gas turbine
Implementation Method 2
the propulsor comprising a fan arranged to be driven by an electric motor
Data Source
Figure 1~2
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AI summary
The present disclosure concerns control a hybrid electric gas turbine system (300) for an aircraft. The system comprises an electric generator (308) and a gas turbine (309) to form a generator system, an electric motor (303) and a fan (302) to form a propulsor (301), a controller (306) and an electric storage unit (307). After receiving a command for a change in demand for thrust, the controller (306) determines an operational profile that minimises a function comprising a measure of fuel supplied to the gas turbine (309), a transfer of electric power from or to the electric storage unit (307) and a difference between measures of current and demanded thrust over a time period. The controller then operates the electric motor (303), gas turbine (309) and electric storage unit (307) according to the determined operational profile over the time period.