Aircraft Starter Generator Sensorless Control
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Solution Overview
Problem
Conventional aircraft starter generator systems lack high power density, efficiency, and dynamic performance in both start and generate modes, and rely on bulky rotor-position sensors for commutation.
Innovation Solution
A bidirectional energy conversion system featuring a three-electric-machine set with a dual-functional exciter stator and a digitally controlled IGBT-based Inverter/Converter/Controller, eliminating the need for mechanical position sensors and incorporating auto-field weakening, vector control, and sensorless commutation techniques to enhance torque and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional starter generator systems use mechanical position sensors for commutation, then reliable control is achieved, but system size and weight increase
Solution Approach 1:
The patent replaces mechanical position sensors with a sensorless control system that uses electrical signals and mathematical algorithms to determine rotor position. The controller estimates rotor position based on current measurements and back-EMF detection, eliminating mechanical sensors while maintaining control reliability through software-based commutation detection.
Solution Approach 2:
The patent introduces an intermediary estimation algorithm that acts as a mediator between electrical measurements and rotor position determination. Instead of directly measuring position mechanically, the system uses electrical current measurements and mathematical models to infer position, providing an indirect but reliable measurement method.
2Adaptability or versatility
If dual-functional windings are implemented in the exciter stator, then start and generate mode requirements are satisfied, but winding complexity increases
Solution Approach 1:
The patent implements a dual-functional exciter stator winding that serves two purposes: during starting mode, it functions as a three-phase AC winding to provide excitation current, and during generate mode, it functions as a single-phase DC winding for voltage regulation. This multi-functional design eliminates the need for separate windings for different operating modes, reducing overall system complexity despite the increased versatility of each individual winding.
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 higher power density, efficiency, and dynamic performance with reduced size and weight, while eliminating the need for mechanical sensors, enabling effective energy conversion in both start and generate modes.
Implementation Method 1
a bidirectional energy conversion brushless electric rotating device that converts electrical energy to mechanical energy in start mode and mechanical energy to electrical energy in generate mode
Implementation Method 2
a Permanent Magnet Generator (PMG)... converts the AC power to the DC power requested on the aircraft in generate mode
Data Source
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AI summary
An aircraft starting and generating system includes a starter/generator that includes a main machine, an exciter, and a permanent magnet generator. The system also includes an inverter/converter/controller that is connected to the starter/generator and that generates AC power to drive the starter/generator in a start mode for starting a prime mover of the aircraft, and that converts AC power, obtained from the starter/generator after the prime mover have been started, to DC power in a generate mode of the starter/generator. The exciter includes a stator and a rotor, and wherein the exciter rotor includes a three-phase AC winding.