Multifunction Power Converter Controller for Aircraft APU Efficiency
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Solution Overview
Problem
Current aircraft electric power systems are inefficient, particularly in providing 400 Hz power at reduced APU speeds, and rely on fuel-burning APUs for environmental control and taxiing, leading to increased fuel consumption and emissions.
Innovation Solution
A high-efficiency power system incorporating a multifunction power converter-controller (MPCC) module that uses ground power to motor the APU generator, enabling reduced-speed operation and electrical power distribution for aircraft systems, including the Environmental Control System and Electric Green Taxi System, while reducing weight and fuel burn.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the APU is sized for worst-case operating conditions at ground altitude and temperature, then it can provide sufficient power for environmental control, but it operates inefficiently at lower speeds leading to increased fuel consumption
Solution Approach 1:
The APU system dynamically adjusts its operating mode based on power requirements. The generator can operate as a motor when ground power is available, allowing the APU to run at reduced speeds for fuel savings while still meeting power demands when needed. This dynamic switching between generation and motor modes resolves the contradiction between reliable power supply and fuel efficiency.
Solution Approach 2:
The system changes the operational parameters of the generator by converting it from generation mode to motor mode using power electronics (MPCC). This parameter change allows the APU to operate at lower speeds when ground power is available, reducing fuel consumption while maintaining the ability to provide full power when required.
2Use of energy by moving object
If the APU runs at lower speeds to save fuel, then fuel consumption decreases, but the generator output frequency drops below the required 400 Hz
Solution Approach 1:
The Multifunction Power Converter-Controller (MPCC) acts as an intermediary between the generator and the aircraft power system. When the generator operates as a motor at reduced speeds, the MPCC manages the power flow and frequency conversion, allowing the APU to run at fuel-efficient speeds while maintaining the required 400 Hz output frequency for aircraft systems.
3Object-generated harmful factors
If the generator is used as a motor driven by ground power, then fuel burn and emissions are reduced, but the system complexity increases
Solution Approach 1:
The generator is designed with multi-functionality, capable of operating both as a power generator and as a motor. The MPCC controls the generator's operation in different modes (generation, motor, and idle) based on system requirements. This universal design reduces emissions by enabling motor operation with ground power while managing complexity through integrated control.
Solution Approach 2:
The system merges the generator and motor functions into a single device, eliminating the need for separate motor and generator components. The MPCC integrates the control of power conversion and generator operation, reducing overall system complexity while enabling the emissions-reducing motor operation capability.
4Speed
If a constant speed drive mechanism is added to maintain 400 Hz output, then frequency stability is improved, but the weight and complexity of the system increase
Solution Approach 1:
The patent replaces the mechanical constant speed drive mechanism with an electrical power conversion system (MPCC). Instead of using mechanical means to maintain constant generator speed for 400 Hz output, the system uses power electronics to convert variable frequency output to stable 400 Hz, significantly reducing weight while maintaining frequency stability.
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 achieves significant weight reduction, fuel savings, and emission reduction by utilizing ground power to operate the APU as a motor, providing efficient 400 Hz power and eliminating the need for fuel-burning APUs during ground operations.
Implementation Method 1
the AC generator is configured to use ground power to run as a motor to provide mechanical power for the APU
Data Source
AI summary
A high efficiency multifunction power system for an aircraft is provided. The system includes an AC generator and a multifunction power converter-controller module including at least one multifunction power converter-controller. The at least one multifunction power converter-controller is configured to function as a power converter and a controller to perform multiple operation modes.