Aircraft Engine Constant Frequency Starter Generator
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Solution Overview
Problem
Aircraft starter/generator systems face challenges in efficiently transitioning between starting and generating modes, particularly in providing consistent frequency and reducing weight and complexity.
Innovation Solution
A constant frequency starter/generator system with a first and second inverter/converter, a DC link, and an electric machine with a synchronous main machine and exciter, operating in distinct modes to manage power conversion efficiently, using solid-state components for reliability and reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pneumatic and mechanical components are used in starter/generator systems, then the system can provide starting torque and power generation, but the weight and complexity of the system increase
Solution Approach 1:
The patent combines the starter motor and generator into a single integrated electric machine assembly, eliminating the need for separate pneumatic and mechanical systems. This merging reduces overall system weight while maintaining both starting torque and power generation capabilities through a unified electromagnetic design.
Solution Approach 2:
The patent replaces traditional mechanical and pneumatic starting components with an electric motor system. The electric motor provides starting torque through electromagnetic fields rather than mechanical linkages or pneumatic actuators, significantly reducing moving mass and system complexity while improving reliability through fewer mechanical wear points.
2Adaptability or versatility
If traditional starter/generator systems operate with variable frequency power, then the system can adapt to engine starting requirements, but the complexity of power conversion increases
Solution Approach 1:
The patent employs a power conversion system that dynamically adapts its operation mode based on system requirements. The converters switch between charging mode (when external power is available) and generating mode (when the engine is running), with the control system automatically adjusting parameters to optimize performance while managing complexity through standardized conversion circuits.
Solution Approach 2:
The patent designs the power conversion system to perform multiple functions using the same hardware components. The converters can operate in bidirectional modes, serving as rectifiers during external power charging and as inverters during engine power generation, eliminating the need for separate conversion systems for each function and reducing overall complexity.
3Productivity
If the starter/generator system transitions between starting and generating modes, then the system can provide both starting torque and power generation, but the transition efficiency and frequency consistency challenge
Solution Approach 1:
The patent incorporates a control system that continuously monitors the operational state and provides feedback to maintain constant frequency output. During mode transitions, the control system adjusts converter switching parameters based on real-time feedback from frequency and voltage sensors, ensuring frequency consistency is maintained throughout the transition from starting to generating mode.
Solution Approach 2:
The patent utilizes parameter changes in the power conversion system to facilitate smooth mode transitions while maintaining frequency consistency. By dynamically adjusting conversion ratios, switching frequencies, and voltage levels during transitions, the system efficiently switches between starting and generating modes while the control system maintains constant output frequency through coordinated parameter modification.
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 sufficient starting torque and steady-state power generation with reduced weight and complexity, replacing traditional pneumatic and mechanical components, enhancing reliability and efficiency.
Implementation Method 1
converting the AC input to a DC output with a first inverter/converter, converting the DC output to a second AC input by supplying the DC output to a second inverter/converter
Implementation Method 2
supplying the second AC output to the main machine to start rotation of the main machine
Implementation Method 3
accelerating the synchronous main machine by supplying a third AC output to the exciter
Data Source
AI summary
A constant frequency starter/generator for a turbine engine includes a first inverter/converter, a second inverter/converter, a DC link electrically connecting the first inverter/converter to the second inverter/converter, and an electric machine having a synchronous main machine, wherein the constant frequency starter/generator is operable in a start mode and a run mode.