Single Motor Drive for Aircraft Starter-Generators
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Solution Overview
Problem
Conventional electric starter-generator systems for aircraft engines require multiple motor drives, leading to increased size, weight, and expense due to independent control of each starter-generator.
Innovation Solution
A single motor drive controls multiple starter-generators by aligning their internal electro-motive forces and using synchronized ac electrical power to reduce waste current and inefficiencies, with control schemes to balance electrical outputs and mechanical power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If each starter-generator is individually controlled by a separate motor drive, then the speed and torque output of each starter-generator can be independently controlled, but the size, weight, and expense of the electric engine starter assembly increases
Solution Approach 1:
The patent combines multiple motor drives into a single motor drive that controls multiple starter-generators. The motor drive outputs three-phase AC power that is distributed to multiple starter-generators, eliminating the need for separate motor drives for each starter-generator. This merging reduces the overall weight, size, and cost while maintaining independent control capability through electrical distribution and control circuitry.
2Ease of operation
If each starter-generator is individually controlled by a separate motor drive, then independent control is achieved, but the size and expense of the electric engine starter assembly increases
Solution Approach 1:
The patent merges multiple motor drives into a single motor drive unit that controls multiple starter-generators through a common electrical output system. The control circuitry manages power distribution to multiple starters, reducing the number of separate drive units and simplifying the overall system architecture while maintaining independent control capability.
3Weight of stationary object
If a single motor drive controls multiple starter-generators, then the size, weight, and expense are reduced, but the internal electro-motive forces must be synchronized to prevent waste current
Solution Approach 1:
The patent employs feedback control mechanisms to monitor and synchronize the electro-motive forces of multiple starter-generators. The control circuitry detects the phase and magnitude of electro-motive forces and adjusts the applied power accordingly to maintain synchronization. This feedback ensures that starter-generators operate in phase, preventing waste current and maximizing efficiency.
Solution Approach 2:
The patent dynamically adjusts electrical parameters (voltage, frequency, phase angle) of the power supplied to each starter-generator based on real-time conditions. By changing these parameters to match the electro-motive force characteristics of each starter-generator, the system maintains synchronization and minimizes waste current while operating with reduced overall system weight.
4Weight of stationary object
If a single motor drive controls multiple starter-generators, then system weight is reduced, but control complexity increases due to synchronization requirements
Solution Approach 1:
The single motor drive is designed with multi-functionality to control multiple starter-generators with different requirements. The control circuitry is universal in nature, capable of adapting to various starter-generator configurations and synchronization requirements through programmable control logic, thereby reducing the need for multiple specialized drive units while managing control complexity.
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 solution reduces the size, weight, and expense of the electric starter-generator system by minimizing waste current and optimizing power distribution across multiple starter-generators.
Implementation Method 1
In a generate mode, the starter-generators convert mechanical energy from rotation of the jet engine into electrical energy for the aircraft
Implementation Method 2
The electric starter-generator system provides torque to the engine to rotate the engine from a zero speed to a speed that is appropriate for starting the engine
Data Source
AI summary
An electrical starter-generator system includes a first starter-generator and a second starter-generator. A single drive controls both the first starter-generator and the second starter-generator such that their electrical current and power inputs are minimized and balanced.