Low-Spool Dual-Voltage Generator for Windmilling Backup Power
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Solution Overview
Problem
Existing aircraft power generation systems, such as ram air turbines, add significant weight and drag to aircraft, and lack efficient dual voltage generation capabilities during normal and wind milling operations.
Innovation Solution
A dual voltage low spool generator system is integrated with the primary fan of a turbofan engine, utilizing a gearbox to transmit power from the fan to a generator, which can produce two different voltage levels based on the engine's operational state through a generator controller and power converter system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ram air turbine is deployed to generate power during engine failure, then backup power is provided to aircraft components, but significant weight and drag are added to the aircraft
Solution Approach 1:
The invention extracts the power generation function from a separate deployable ram air turbine and integrates it into the existing low spool fan of the turbofan engine. By utilizing the fan's existing structure and rotation during windmilling conditions, the system eliminates the need for a separate backup power generation device, thereby reducing aircraft weight while maintaining reliability
Solution Approach 2:
The low spool fan serves multiple functions: it provides normal propulsion assistance during engine operation and acts as a backup power generation device during engine failure through windmilling. This multi-functionality eliminates the need for dedicated backup equipment, reducing overall system weight
2Reliability
If a ram air turbine is deployed to generate power during engine failure, then backup power is provided to aircraft components, but significant drag is added to the aircraft
Solution Approach 1:
The invention removes the need for a separate deployable ram air turbine by extracting the backup power function from it and integrating it into the existing low spool fan. Since the fan is already part of the engine structure and rotates during windmilling conditions, no additional drag-inducing components are required
Solution Approach 2:
The invention converts the windmilling rotation (which occurs naturally during engine failure due to airflow) into useful electrical power. Instead of treating the unpowered fan rotation as a loss, the system captures this kinetic energy through the integrated generator to provide backup power, eliminating the need for drag-producing deployable turbines
3Productivity
If a single voltage generator is used during normal operation, then power is provided at standard voltage levels, but dual voltage generation capability is lost for different operational states
Solution Approach 1:
The invention implements a dynamic voltage generation system that automatically adjusts output voltage based on operational conditions. The controller monitors engine state and generator speed, switching between high voltage mode during normal operation and low voltage mode during windmilling, allowing the system to adapt to different operational requirements without manual intervention
Solution Approach 2:
The system changes the electrical output parameters (voltage and current) based on the generator's rotational speed and operational state. During normal operation, the generator produces high voltage at higher speeds, while during windmilling at lower speeds, it produces lower voltage, optimizing power delivery for each condition
4Power
If the generator is coupled directly to the high spool, then power transmission is direct, but the generator cannot utilize low spool fan rotation during windmilling conditions
Solution Approach 1:
The invention segments the engine's rotational systems by coupling the generator to the low spool fan rather than the high spool. This segmentation allows the low spool to independently rotate during windmilling conditions and drive the generator, while the high spool remains disconnected for normal propulsion, ensuring backup power availability without compromising primary power transmission efficiency
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 provides efficient dual voltage generation, reducing weight and drag compared to traditional ram air turbines, while ensuring continuous power supply to aircraft components during both normal and engine failure conditions.
Implementation Method 1
A dual voltage low spool generator system is integrated with the primary fan of a turbofan engine, utilizing a gearbox to transmit power from the fan to a generator
Data Source
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AI summary
Systems (300) and methods (400) for dual voltage power generation are provided. Aspects include a generator (302) having an input connected to an engine to receive rotational energy proportional to a rotation speed of a fan and having an output through which electrical energy is output, a rectifier circuit (306) having an input coupled to the output of the generator and a rectifier output that outputs rectified power, a bypass switch (308) connected to the output of rectifier and operates in a plurality of states including a normal operation state where the rectified power is provided a power converter and a bypass state where the rectified power is provided directly to a load, and a controller configured to determine an occurrence of an event associated with the engine, and operate the bypass switch (308) in the bypass state based on the occurrence of the event associated with the engine.