Aircraft Propulsion System Load Fluctuation Control
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Solution Overview
Problem
Current aircraft propulsion systems face challenges in managing spike-like load fluctuations during takeoff, landing, and hovering, which require large batteries and cooling systems, leading to increased weight and reduced battery life due to reliance on electric power from batteries to compensate for load fluctuations.
Innovation Solution
The system incorporates a gas turbine element, generator, battery, electric motor, flight state detection unit, load fluctuation detection unit, and operating point control unit that dynamically adjusts power operating points between two defined lines to utilize kinetic energy from the gas turbine element instead of battery power, minimizing battery size and cooling system requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric power from the battery is used to compensate for load fluctuation, then the load fluctuation can be coped with, but the battery capacity needs to be increased and the battery weight increases
Solution Approach 1:
The gas turbine engine operates in advance at a higher output level than the average required power, storing excess kinetic energy in the rotating components (compressor and turbine). When load fluctuation occurs, this pre-stored kinetic energy is quickly converted to electric energy by the generator, providing immediate compensation without requiring large battery capacity.
Solution Approach 2:
The invention introduces the gas turbine engine and generator as intermediary components between the load fluctuation and the battery. Instead of using the battery directly to compensate for load fluctuation, the system uses the gas turbine's kinetic energy as an intermediate energy source, which reduces the burden on the battery and allows for smaller battery capacity.
2Reliability
If electric power from the battery is used to compensate for load fluctuation, then the load fluctuation can be coped with, but the battery life is reduced
Solution Approach 1:
The gas turbine engine prepares energy in advance by operating at elevated output levels, storing kinetic energy in its rotating components. This preliminary energy storage eliminates the need for frequent and intensive battery discharge during load fluctuations, thereby reducing battery stress and extending battery life.
Solution Approach 2:
The gas turbine engine acts as an intermediary that absorbs the stress of load fluctuations. By using the gas turbine's kinetic energy to compensate for load changes, the battery is protected from frequent deep cycling and high-rate discharge, which are the main causes of battery degradation and shortened lifespan.
3Reliability
If the battery capacity is increased to cope with load fluctuation, then the load fluctuation can be handled, but the cooling system becomes large
Solution Approach 1:
The gas turbine engine pre-stores energy in its rotating mass, providing a rapid response capability for load fluctuations. This reduces the required battery capacity to a level where the associated cooling system remains compact, as the battery no longer needs to handle the full burden of load compensation.
Solution Approach 2:
The gas turbine engine serves as an intermediary that shares the load compensation duty with the battery. This division of labor allows the battery to be sized smaller, which in turn allows for a more compact cooling system, while still maintaining the overall system's ability to handle load fluctuations effectively.
4Power
If fuel flow rate is increased to follow load fluctuation, then the output can be adjusted, but the response time is insufficient for spike-like fluctuations
Solution Approach 1:
The gas turbine engine maintains a reserve of kinetic energy in its rotating components by operating at a slightly elevated output level in advance. This pre-stored energy can be instantly converted to electrical energy through the generator, providing a rapid response to spike-like load fluctuations without the delay associated with increasing fuel flow rate.
Solution Approach 2:
The invention replaces the slow thermal-mechanical response of increasing fuel flow rate with a faster electro-mechanical response. By using the generator to convert the gas turbine's kinetic energy into electrical energy, the system achieves a much faster response speed that can keep up with spike-like load fluctuations, effectively substituting the slow fuel adjustment mechanism with a quicker energy conversion process.
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 allows for efficient management of load fluctuations without increasing battery size or reducing battery life, improving responsiveness and fuel efficiency by converting kinetic energy into electric energy and reducing battery usage frequency.
Implementation Method 1
a generator connected to the gas turbine element via a rotation shaft
Implementation Method 2
an electric motor driven by at least one of the electric power from the generator and the electric power from the battery
Data Source
AI summary
A load fluctuation detection unit that detects a load fluctuation of an aircraft, and an operating point control unit that controls a power operating point defined by a torque and rotation speed based on a flight state. The operating point control unit sets a target power operating point (62) for coping with a load with respect to an initial power operating point (61) in an operating point map (40) when the load has fluctuated. The operating point control unit moves the power operating point from the initial power operating point (61) on a first operating line (41) to the target power operating point (62) on a second operating line (42), to a return power operating point (63) on the first operating line (41) while keeping a torque T constant, and then to the initial power operating point (61) along the first operating line (41).