Aircraft Propulsion Power Split Control for Step-Load Response
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Solution Overview
Problem
Conventional propulsion systems for aircraft face challenges in quickly responding to step-load changes during takeoff, landing, and hovering, which results in inefficient fuel flow control, increased battery size and weight, and reduced battery life.
Innovation Solution
The propulsion system incorporates a gas turbine element, a power generator, a battery, an electric motor, and a sophisticated control unit that dynamically adjusts power operating points by changing fuel flow within predetermined fuel lines, allowing for rapid load changes without exceeding safe operating limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the gas turbine engine is accelerated by increasing the fuel flow rate, then the power output increases, but the response time is insufficient to quickly follow step-load changes
Solution Approach 1:
The battery is pre-charged during cruising flight when power demand is low, storing electric energy in advance. When step-load changes occur during takeoff or landing, the pre-charged battery provides immediate supplemental power, enabling the gas turbine engine to respond faster to load changes without exceeding fuel flow limits.
Solution Approach 2:
The propulsion system alternates between different power sources based on flight conditions: the gas turbine engine provides base power during cruising, while the battery provides supplemental power during transient high-demand phases. This periodic switching optimizes the utilization of each power source according to the specific flight phase requirements.
2Power
If the battery capacity is increased to supplement power during load changes, then the power supply capability improves, but the battery size, cooling system size, and weight increase
Solution Approach 1:
Instead of sizing the battery for complete power supply during all transient conditions, the system uses partial action by providing only supplemental power during critical transient phases. The battery capacity is optimized to cover the power gap during these specific periods rather than designing for full power requirements, reducing overall battery size and weight.
Solution Approach 2:
The control system dynamically adjusts the power distribution parameters between the gas turbine engine and battery based on real-time flight conditions. By changing the operating parameters (power split ratio) according to flight phase, the system optimizes battery utilization and minimizes the required battery capacity while maintaining adequate power supply capability during transients.
3Power
If the battery capacity is increased to handle load changes, then the power reserve increases, but the battery life is shortened
Solution Approach 1:
The battery is pre-charged during low-demand cruising phases, preparing energy reserves in advance rather than relying on high-rate discharge from a large capacity battery. This preliminary energy storage allows the use of a smaller battery that undergoes fewer deep discharge cycles, extending its operational life.
Solution Approach 2:
The system maintains continuous useful action by keeping the battery charged during cruising flight, ensuring energy availability without requiring excessive battery capacity. This continuous charging during normal operation reduces the depth of discharge during transient events, which extends battery life by minimizing stress on the battery cells.
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 configuration enables the propulsion system to quickly follow load changes, reduce the size and weight of the battery and its cooling system, and extend battery life by optimizing fuel efficiency and power distribution.
Implementation Method 1
a gas turbine element 2 including a compressor 21 and a turbine 22 that rotates integrally with the compressor
Implementation Method 2
a power generator 3 connected to the gas turbine element 2 through a rotation shaft 25
Implementation Method 3
a battery 5 accumulating electric power generated by the power generator 3
Implementation Method 4
an electric motor 7 driven by at least one of electric power from the power generator 3 and electric power from the battery 5
Data Source
AI summary
The propulsion system have a load change detecting unit detecting a load change and an operating point control unit controlling power operating points defined using a torque T and a rotation number Ne. The operating point control unit calculates target power operating points 44 and 54 corresponding to the load after change for first power operating points 41 and 51 that are current power operating points in a case in which a change in the load is detected by the load change detecting unit. By changing the fuel flow in a range not exceeding a predetermined fuel line, the operating point control unit moves the power operating points from first power operating points 41 and 51 to second power operating points 42 and 52, third power operating points 43 and 53, and target power operating points 44 and 54 in order.