Asynchronous Starter-Generator with Dual Stator Windings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current turbomachine starting systems, particularly those using pneumatic or brush-type electric motors, lack the ability to control torque and speed profiles effectively, are unreliable, and struggle with high starting torque and power requirements, necessitating the development of more sophisticated and efficient solutions like brushless starter-generators.
Innovation Solution
The use of an asynchronous machine with an inverter and a dual stator winding configuration, where one stator winding is used for starting and magnetization in motor mode and the other for power supply in generator mode, eliminating the need for external magnetization sources and optimizing mass, efficiency, and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a synchronous machine with permanent magnets is used, then control precision and reliability are improved, but safety problems arise due to fire risk in case of failure
Solution Approach 1:
The patent replaces permanent magnets with an asynchronous machine that uses a squirrel cage rotor. This eliminates the fire risk associated with permanent magnets while maintaining the ability to provide controlled starting torque and power for turbomachines. The asynchronous machine, though less efficient in terms of power density, provides adequate performance without the safety hazards of permanent magnet materials.
2Adaptability or versatility
If an asynchronous machine with multiple stator windings is used, then versatility is improved, but device complexity increases due to multiple inverters and rectifiers
Solution Approach 1:
The patent employs a single inverter that performs multiple functions: it provides magnetizing current to the auxiliary winding during motor operation, controls the main winding for torque production, and manages power flow during generator operation. This multi-functional approach eliminates the need for separate inverters and rectifiers, reducing system complexity while maintaining the ability to operate in both motor and generator modes with controlled torque and power.
Solution Approach 2:
The patent combines the functions of multiple windings (main and auxiliary) and a single inverter into an integrated system. The auxiliary winding serves dual purposes: providing magnetizing flux during motor operation and enabling controlled power output during generation. This merging of functions reduces the number of separate components needed compared to traditional multi-winding asynchronous starters.
3Reliability
If brushless starter-generators are used, then reliability is improved, but mass and dimensions increase
Solution Approach 1:
The patent replaces the mechanical brush and commutator system with a brushless asynchronous machine driven by power electronics. The inverter provides electronic commutation, eliminating the need for physical brushes while maintaining reliable operation. Although brushless designs typically increase mass due to additional components, the use of a simplified asynchronous machine topology with integrated windings and a single inverter mitigates this mass penalty compared to conventional brushless synchronous starter-generators.
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
This configuration provides a reliable, efficient, and cost-effective solution for turbomachine starter-generators, capable of managing both starting and power generation tasks with improved control and reduced complexity, mass, and volume, while ensuring galvanic isolation and voltage adaptation without additional converters.
Implementation Method 1
an inverter (3) arranged between the electrical source (12, 13, 14) and the asynchronous machine (1, 11, 21), the inverter (3) having at least two AC terminals coupled to the asynchronous machine (1, 11, 21) and at least two DC terminals coupled to a DC bus (7)... an inverter control unit (4) configured such that the inverter (3) outputs a starting current in motor mode and a magnetisation current in generator mode
Implementation Method 2
configured so as to operate in generator mode after the starting phase of the turbomachine in order to supply power to an electrical load (15, 16)... at least one second stator winding (B1, B2, B3) connected to the electrical load (15, 16) in generator mode
Implementation Method 3
an inverter (3) arranged between the electrical source (12, 13, 14) and the asynchronous machine (1, 11, 21), the inverter (3) having at least two AC terminals coupled to the asynchronous machine (1, 11, 21) and at least two DC terminals coupled to a DC bus (7)
Data Source
AI summary
A generator starter of a turbomachine, including an asynchronous electric machine configured so as to operate in motor mode during a starting phase of the turbomachine while being supplied by an electrical source, and so as to operate in generator mode after the starting phase of the turbomachine in order to supply an electrical load. An inverter is arranged between the electrical source and the asynchronous machine with at least two alternating current terminals coupled to the asynchronous machine, and a control unit for the inverter configured to supply the asynchronous machine with a starting current in motor mode and a magnetisation current in generator mode. The asynchronous machine includes at least one first stator winding connected to the alternating current terminals to be supplied with the starting current in motor mode and with the magnetisation current in generator mode, and at least one second stator winding connected to the electrical load in generator mode.